<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with WebFilings-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://www.enphase.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:href="enph-20121231.xsd#CommitmentsAndContingenciesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConcentrationOfCreditRiskAndMajorCustomersNarrativeDetails" xlink:href="enph-20121231.xsd#ConcentrationOfCreditRiskAndMajorCustomersNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedBalanceSheets" xlink:href="enph-20121231.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="enph-20121231.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedStatementOfStockholdersEquity" xlink:href="enph-20121231.xsd#ConsolidatedStatementOfStockholdersEquity" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedStatementOfStockholdersEquityParenthetical" xlink:href="enph-20121231.xsd#ConsolidatedStatementOfStockholdersEquityParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="enph-20121231.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedStatementsOfComprehensiveLoss" xlink:href="enph-20121231.xsd#ConsolidatedStatementsOfComprehensiveLoss" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConsolidatedStatementsOfOperations" xlink:href="enph-20121231.xsd#ConsolidatedStatementsOfOperations" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/ConvertibleFacilityNarrativeDetails" xlink:href="enph-20121231.xsd#ConvertibleFacilityNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/FairValueMeasurementsHeirarchyDetails" xlink:href="enph-20121231.xsd#FairValueMeasurementsHeirarchyDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/FairValueMeasurementsSummaryOfOpenForeignCurrencyForwardContractsDetails" xlink:href="enph-20121231.xsd#FairValueMeasurementsSummaryOfOpenForeignCurrencyForwardContractsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/FairValueMeasurementsTables" xlink:href="enph-20121231.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/GeographicInformationLongLivedAssetsDetails" xlink:href="enph-20121231.xsd#GeographicInformationLongLivedAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/GeographicInformationNarrativeDetails" xlink:href="enph-20121231.xsd#GeographicInformationNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/GeographicInformationNetRevenuesDetails" xlink:href="enph-20121231.xsd#GeographicInformationNetRevenuesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:href="enph-20121231.xsd#IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/IncomeTaxesEffectiveIncomeTaxReconciliationDetails" xlink:href="enph-20121231.xsd#IncomeTaxesEffectiveIncomeTaxReconciliationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/IncomeTaxesNarrativeDetails" xlink:href="enph-20121231.xsd#IncomeTaxesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/Inventory" xlink:href="enph-20121231.xsd#Inventory" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/LongTermDebtNarrativeDetails" xlink:href="enph-20121231.xsd#LongTermDebtNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/LongTermDebtScheduleOfDebtDetails" xlink:href="enph-20121231.xsd#LongTermDebtScheduleOfDebtDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/LongTermDebtScheduleOfMaturitiesDetails" xlink:href="enph-20121231.xsd#LongTermDebtScheduleOfMaturitiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/LongTermDebtTables" xlink:href="enph-20121231.xsd#LongTermDebtTables" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/NetLossPerShareAttributableToCommonStockholdersNarrativeDetails" xlink:href="enph-20121231.xsd#NetLossPerShareAttributableToCommonStockholdersNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/NetLossPerShareAttributableToCommonStockholdersPotentialCommonSharesOutstandingExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:href="enph-20121231.xsd#NetLossPerShareAttributableToCommonStockholdersPotentialCommonSharesOutstandingExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/OrganizationAndDescriptionOfBusiness" xlink:href="enph-20121231.xsd#OrganizationAndDescriptionOfBusiness" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/PropertyAndEquipmentNetNarrativeDetails" xlink:href="enph-20121231.xsd#PropertyAndEquipmentNetNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails" xlink:href="enph-20121231.xsd#PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/QuarterlyFinancialInformation" xlink:href="enph-20121231.xsd#QuarterlyFinancialInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/QuarterlyFinancialInformationDetails" xlink:href="enph-20121231.xsd#QuarterlyFinancialInformationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/QuarterlyFinancialInformationTables" xlink:href="enph-20121231.xsd#QuarterlyFinancialInformationTables" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:href="enph-20121231.xsd#RelatedPartyTransactionsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationExpenseByAwardTypeDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationExpenseByAwardTypeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationNarrativeDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationRangeOfExercisePriceDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationRangeOfExercisePriceDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationStockOptionActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:href="enph-20121231.xsd#StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockholdersEquityAndWarrantsNarrativeDetails" xlink:href="enph-20121231.xsd#StockholdersEquityAndWarrantsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockholdersEquityAndWarrantsSummaryOfChangesInConvertibleStockWarrantLiabilityDetails" xlink:href="enph-20121231.xsd#StockholdersEquityAndWarrantsSummaryOfChangesInConvertibleStockWarrantLiabilityDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockholdersEquityAndWarrantsTables" xlink:href="enph-20121231.xsd#StockholdersEquityAndWarrantsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/StockholdersEquityAndWarrantsValuationAssumptionsOfConvertiblePreferredStockWarrantsUnderMonteCarloSimulationModelDetails" xlink:href="enph-20121231.xsd#StockholdersEquityAndWarrantsValuationAssumptionsOfConvertiblePreferredStockWarrantsUnderMonteCarloSimulationModelDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/SummaryOfInventoryDetails" xlink:href="enph-20121231.xsd#SummaryOfInventoryDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:href="enph-20121231.xsd#SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="enph-20121231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/WarrantyObligationsNarrativeDetails" xlink:href="enph-20121231.xsd#WarrantyObligationsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/WarrantyObligationsSummaryOfWarrantyObligationsDetails" xlink:href="enph-20121231.xsd#WarrantyObligationsSummaryOfWarrantyObligationsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.enphase.com/role/WarrantyObligationsTables" xlink:href="enph-20121231.xsd#WarrantyObligationsTables" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <definitionLink xlink:role="http://www.enphase.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:type="extended">
    <loc xlink:href="enph-20121231.xsd#enph_CommitmentsAndContingenciesLineItems" xlink:label="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:type="locator" />
    <loc xlink:href="enph-20121231.xsd#enph_CommitmentsAndContingenciesTable" xlink:label="loc_enph_CommitmentsAndContingenciesTable_B4230F57FA6E436D60DB21D5F42C752B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_enph_CommitmentsAndContingenciesTable_B4230F57FA6E436D60DB21D5F42C752B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_51D14F595EE5457178AE21D5F434D3E8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_enph_CommitmentsAndContingenciesTable_B4230F57FA6E436D60DB21D5F42C752B" xlink:to="loc_us-gaap_RangeAxis_51D14F595EE5457178AE21D5F434D3E8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_683C0709BD439CDBF20121D5F4347788_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_51D14F595EE5457178AE21D5F434D3E8" xlink:to="loc_us-gaap_RangeMember_683C0709BD439CDBF20121D5F4347788_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_683C0709BD439CDBF20121D5F4347788" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_51D14F595EE5457178AE21D5F434D3E8" xlink:to="loc_us-gaap_RangeMember_683C0709BD439CDBF20121D5F4347788" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_2BE72DE4A3EB46E157D821D5F43443A7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_683C0709BD439CDBF20121D5F4347788" xlink:to="loc_us-gaap_MaximumMember_2BE72DE4A3EB46E157D821D5F43443A7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLeasesRentExpenseNet" xlink:label="loc_us-gaap_OperatingLeasesRentExpenseNet_F06B82BDA291F05B32FB21D92AFD323A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_us-gaap_OperatingLeasesRentExpenseNet_F06B82BDA291F05B32FB21D92AFD323A" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AreaOfRealEstatePropertyCompanyAgreedToLease" xlink:label="loc_enph_AreaOfRealEstatePropertyCompanyAgreedToLease_1121956703B880BDA4CD21D92AFD0D2C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_enph_AreaOfRealEstatePropertyCompanyAgreedToLease_1121956703B880BDA4CD21D92AFD0D2C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PurchaseObligation" xlink:label="loc_us-gaap_PurchaseObligation_AF94C0EB0E96D87E56F521D92AFD2C00" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_us-gaap_PurchaseObligation_AF94C0EB0E96D87E56F521D92AFD2C00" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LongTermPurchaseCommitmentTimePeriodMaximum" xlink:label="loc_enph_LongTermPurchaseCommitmentTimePeriodMaximum_53A6BC51F1B858F83EF221D92AFECAC6" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_enph_LongTermPurchaseCommitmentTimePeriodMaximum_53A6BC51F1B858F83EF221D92AFECAC6" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_PurchaseObligationCancelableAmount" xlink:label="loc_enph_PurchaseObligationCancelableAmount_5D48425B24E0A1F7D58721D92AFECB1F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_enph_PurchaseObligationCancelableAmount_5D48425B24E0A1F7D58721D92AFECB1F" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_PurchaseObligationCancellationPenaltyMaximum" xlink:label="loc_enph_PurchaseObligationCancellationPenaltyMaximum_F89CB478E9B6616F0BFD21D92AFEB089" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_CommitmentsAndContingenciesLineItems_AE9E378481BDDBE5A4CC21D92AFB1923" xlink:to="loc_enph_PurchaseObligationCancellationPenaltyMaximum_F89CB478E9B6616F0BFD21D92AFEB089" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConcentrationOfCreditRiskAndMajorCustomersNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_053F6AC467EEA5321FE23776FA7C0DC1" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:label="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_91A6AF8DF6E1C97F7CF93776FA7BC1B7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_053F6AC467EEA5321FE23776FA7C0DC1" xlink:to="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_91A6AF8DF6E1C97F7CF93776FA7BC1B7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_DBB06D83363D2FAACE17378C197770C5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_91A6AF8DF6E1C97F7CF93776FA7BC1B7" xlink:to="loc_us-gaap_MajorCustomersAxis_DBB06D83363D2FAACE17378C197770C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorCustomersAxis_DBB06D83363D2FAACE17378C197770C5" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorCustomersAxis_DBB06D83363D2FAACE17378C197770C5" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_CustomerWithHighestBalanceDueMember" xlink:label="loc_enph_CustomerWithHighestBalanceDueMember_6AA4F37B175287A398E13776FA7C501E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:to="loc_enph_CustomerWithHighestBalanceDueMember_6AA4F37B175287A398E13776FA7C501E" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_CustomerWithSecondHighestBalanceDueMember" xlink:label="loc_enph_CustomerWithSecondHighestBalanceDueMember_24976E9C2E0740FC47823776FA7C5563" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:to="loc_enph_CustomerWithSecondHighestBalanceDueMember_24976E9C2E0740FC47823776FA7C5563" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LargestCustomerAccountingForMostRevenueMember" xlink:label="loc_enph_LargestCustomerAccountingForMostRevenueMember_54382C6AAD713B1282A83776FA7CB29A" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:to="loc_enph_LargestCustomerAccountingForMostRevenueMember_54382C6AAD713B1282A83776FA7CB29A" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_SecondLargestCustomerAccountingForMostRevenueMember" xlink:label="loc_enph_SecondLargestCustomerAccountingForMostRevenueMember_C2CC8763F9859395A1943776FA7C5E2B" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:to="loc_enph_SecondLargestCustomerAccountingForMostRevenueMember_C2CC8763F9859395A1943776FA7C5E2B" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ThirdLargestCustomerAccountingForMostRevenueMember" xlink:label="loc_enph_ThirdLargestCustomerAccountingForMostRevenueMember_9293B84F1031648D180A3776FA7CAB14" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_1BFAC37C9E0900F47B7C378C19806D40" xlink:to="loc_enph_ThirdLargestCustomerAccountingForMostRevenueMember_9293B84F1031648D180A3776FA7CAB14" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_04A54FC1292892F537613776FA7BB3D4" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_91A6AF8DF6E1C97F7CF93776FA7BC1B7" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_04A54FC1292892F537613776FA7BB3D4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_04A54FC1292892F537613776FA7BB3D4" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_04A54FC1292892F537613776FA7BB3D4" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="loc_us-gaap_AccountsReceivableMember_EAB3B8E3CBAEFD6B5F3C3776FA7C9AB3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1" xlink:to="loc_us-gaap_AccountsReceivableMember_EAB3B8E3CBAEFD6B5F3C3776FA7C9AB3" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_NetRevenueMember" xlink:label="loc_enph_NetRevenueMember_293A5292CBA6BDFB63363776FA7CFA94" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_DC11C1DC511B8B0659D13776FA7CCCE1" xlink:to="loc_enph_NetRevenueMember_293A5292CBA6BDFB63363776FA7CFA94" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_3D0F380E61B8E0A8D1523776FA7CABF2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_91A6AF8DF6E1C97F7CF93776FA7BC1B7" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_3D0F380E61B8E0A8D1523776FA7CABF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_3D0F380E61B8E0A8D1523776FA7CABF2" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_3D0F380E61B8E0A8D1523776FA7CABF2" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditConcentrationRiskMember" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_A948CCC5E18C1D268ACE378D8DAD35D5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_A948CCC5E18C1D268ACE378D8DAD35D5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_3B04704C3EEF188A83623776FA7CC114" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_BC56BBAD0E7696A3F3143776FA7C6DD0" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_3B04704C3EEF188A83623776FA7CC114" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_64D2289CD313E82A87A03776FA7C6565" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_053F6AC467EEA5321FE23776FA7C0DC1" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_64D2289CD313E82A87A03776FA7C6565" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_NumberOfCustomersConsideredToGiveRiseToConcentrationRisk" xlink:label="loc_enph_NumberOfCustomersConsideredToGiveRiseToConcentrationRisk_19A7E2B723558074A5C43776FA7CD416" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_053F6AC467EEA5321FE23776FA7C0DC1" xlink:to="loc_enph_NumberOfCustomersConsideredToGiveRiseToConcentrationRisk_19A7E2B723558074A5C43776FA7CD416" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_1B33C8363593ED6BAC9837707AF2D58F" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_191A5EC25A33E991682237707AF2221A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_1B33C8363593ED6BAC9837707AF2D58F" xlink:to="loc_us-gaap_StatementTable_191A5EC25A33E991682237707AF2221A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_ADEC0AF63D77EB7EE00737707AF22B83" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_191A5EC25A33E991682237707AF2221A" xlink:to="loc_us-gaap_StatementClassOfStockAxis_ADEC0AF63D77EB7EE00737707AF22B83" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ADEC0AF63D77EB7EE00737707AF22B83" xlink:to="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ADEC0AF63D77EB7EE00737707AF22B83" xlink:to="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_066EB78CB060E58240C437707AF2AE2B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_066EB78CB060E58240C437707AF2AE2B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_AB40172DCA5697A132EC37707AF28C08" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_B5CD454EBBEB24AE5DA037707AF25046" xlink:to="loc_us-gaap_PreferredStockMember_AB40172DCA5697A132EC37707AF28C08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1B33C8363593ED6BAC9837707AF2D58F" xlink:to="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:to="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_52BDFC5AD3A858B3EEAD37707AF2987C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_52BDFC5AD3A858B3EEAD37707AF2987C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_0D955E814F5F715F9A3D37707AF38DA8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_0D955E814F5F715F9A3D37707AF38DA8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_E8498A7F08030A9975AA37707AF3CC65" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:to="loc_us-gaap_InventoryNet_E8498A7F08030A9975AA37707AF3CC65" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_E00D874FFCBF6AA01DF637707AF30DCD" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_E00D874FFCBF6AA01DF637707AF30DCD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_0841873414DD77DABF3837707AF382B6" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_9A1A7D973B579E4EB84E37707AF24F22" xlink:to="loc_us-gaap_AssetsCurrent_0841873414DD77DABF3837707AF382B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_47EFECE7D22880412EAE37707AF365FD" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_47EFECE7D22880412EAE37707AF365FD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_174AF88A5CBF91E7EF0137707AF33B5B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_174AF88A5CBF91E7EF0137707AF33B5B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_63B5226BC332812040E637707AF3D130" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2D84863B97CCA8C5AD7C37707AF2EAA5" xlink:to="loc_us-gaap_Assets_63B5226BC332812040E637707AF3D130" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1B33C8363593ED6BAC9837707AF2D58F" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_62179448D8D007E1633437707AF3EABF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_AccountsPayableCurrent_62179448D8D007E1633437707AF3EABF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_89560D4D541B9F5167B537707AF3EBE8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_89560D4D541B9F5167B537707AF3EBE8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_B7454520981AC87BE73B37707AF36486" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_DeferredRevenueCurrent_B7454520981AC87BE73B37707AF36486" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LoansPayableCurrent" xlink:label="loc_us-gaap_LoansPayableCurrent_CD8BD661DA9A6F68E4D637707AF44BBB" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_LoansPayableCurrent_CD8BD661DA9A6F68E4D637707AF44BBB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_D1E83C0221994957D54637707AF4876E" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_D1E83C0221994957D54637707AF4876E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_145EB32BAFE1D7F815CA37707AF4AEF0" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_148E89808F5B7FE64A7037707AF320AB" xlink:to="loc_us-gaap_LiabilitiesCurrent_145EB32BAFE1D7F815CA37707AF4AEF0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_B971103CEC87F1F65FD737707AF4789C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_B971103CEC87F1F65FD737707AF4789C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductWarrantyAccrualNoncurrent" xlink:label="loc_us-gaap_ProductWarrantyAccrualNoncurrent_2AA196FF7F4D1E97793437707AF4BE00" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_ProductWarrantyAccrualNoncurrent_2AA196FF7F4D1E97793437707AF4BE00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_842C8AC00ABE1C97F09037707AF4F500" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_842C8AC00ABE1C97F09037707AF4F500" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermLoansPayable" xlink:label="loc_us-gaap_LongTermLoansPayable_28EBBB64C1EDC5C812F537707AF4E3DA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_LongTermLoansPayable_28EBBB64C1EDC5C812F537707AF4E3DA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleLongTermNotesPayable" xlink:label="loc_us-gaap_ConvertibleLongTermNotesPayable_9D543B085041A2AE5DFC37707AF44C41" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_ConvertibleLongTermNotesPayable_9D543B085041A2AE5DFC37707AF44C41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_D4B8B888B6DEDC091F6237707AF4868D" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_FBCAFACDDD4C70E49B4B37707AF422E6" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_D4B8B888B6DEDC091F6237707AF4868D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_8AC92E11126468679AC237707AF43B2F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_Liabilities_8AC92E11126468679AC237707AF43B2F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_A54B8F1285205A74DE5D37707AF4C62F" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_CommitmentsAndContingencies_A54B8F1285205A74DE5D37707AF4C62F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_129AC6F4421FEDEB100437707AF450F0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_PreferredStockValue_129AC6F4421FEDEB100437707AF450F0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_733DA13E4793385EB59C37707AF50F9B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_CommonStockValue_733DA13E4793385EB59C37707AF50F9B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_AF7224DF5041A816A20437707AF5EC88" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_AdditionalPaidInCapital_AF7224DF5041A816A20437707AF5EC88" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_2FF74F8CA0CA007279E837707AF5062B" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_2FF74F8CA0CA007279E837707AF5062B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_BB094A91708C74605B2F37707AF5FCF7" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_BB094A91708C74605B2F37707AF5FCF7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_DDC0BFA7A3B2093383C537707AF5C6EC" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_A86C0277ABB34B45C26437707AF43C04" xlink:to="loc_us-gaap_StockholdersEquity_DDC0BFA7A3B2093383C537707AF5C6EC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_06177846730CE159828737707AF5C90E" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_57CBE6C5BCF0B9F7748A37707AF3705B" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_06177846730CE159828737707AF5C90E" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_DCBE180C7D7A2A821ACB4AD13E2E6379" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_StatementTable_DCBE180C7D7A2A821ACB4AD13E2E6379" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_9093C1ECB8A3DD52F8594AD13E2EF131" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_DCBE180C7D7A2A821ACB4AD13E2E6379" xlink:to="loc_us-gaap_StatementClassOfStockAxis_9093C1ECB8A3DD52F8594AD13E2EF131" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EE4A45F782875B98DB384AD13E2FE5EA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_9093C1ECB8A3DD52F8594AD13E2EF131" xlink:to="loc_us-gaap_ClassOfStockDomain_EE4A45F782875B98DB384AD13E2FE5EA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EE4A45F782875B98DB384AD13E2FE5EA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_9093C1ECB8A3DD52F8594AD13E2EF131" xlink:to="loc_us-gaap_ClassOfStockDomain_EE4A45F782875B98DB384AD13E2FE5EA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_A9FC632CC8FEF330F25F4AD13E2F1A56" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EE4A45F782875B98DB384AD13E2FE5EA" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_A9FC632CC8FEF330F25F4AD13E2F1A56" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_9DAAA993502150F8D6604AD13E2FBCBB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_9DAAA993502150F8D6604AD13E2FBCBB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_37D5165C96C536C422494AD13E2F0FEF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_37D5165C96C536C422494AD13E2F0FEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_6CFCB9616B22A80D8EED4AD13E2FAAB7" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_6CFCB9616B22A80D8EED4AD13E2FAAB7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_6C21213393271267C91C4AD13E2F9BAA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_CommonStockSharesIssued_6C21213393271267C91C4AD13E2F9BAA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_345D4D071CAFBD6D5C6D4AD13E2FC4A9" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_345D4D071CAFBD6D5C6D4AD13E2FC4A9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_F72146FBF63724D6CEC24AD13E2F2E38" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_F72146FBF63724D6CEC24AD13E2F2E38" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_826B71474509E2BD7B264AD13E2FB70F" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_826B71474509E2BD7B264AD13E2FB70F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_8F69895D23F09EBE3D134AD13E2FB730" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_PreferredStockSharesIssued_8F69895D23F09EBE3D134AD13E2FB730" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_54A2066B01001C0EB9374AD13E2F150E" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_07FA6D134669A1C450124AD13E2FE251" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_54A2066B01001C0EB9374AD13E2F150E" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedStatementOfStockholdersEquity" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_CF083511F4D0EC5B4AE7374BA5A9919A" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_9258D3D2027BC715639D374BA5A7F99B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_CF083511F4D0EC5B4AE7374BA5A9919A" xlink:to="loc_us-gaap_StatementTable_9258D3D2027BC715639D374BA5A7F99B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_6B1A633A8618213CC47F374BA5A80120" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9258D3D2027BC715639D374BA5A7F99B" xlink:to="loc_us-gaap_StatementClassOfStockAxis_6B1A633A8618213CC47F374BA5A80120" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_6B1A633A8618213CC47F374BA5A80120" xlink:to="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_6B1A633A8618213CC47F374BA5A80120" xlink:to="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SeriesEPreferredStockMember" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_994C34599DD25295E635374BA5A8134C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_994C34599DD25295E635374BA5A8134C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_994D4F5428E1BACB7B5B374BA5A8F0F3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EFC2557AA3E6560A488B374BA5A83420" xlink:to="loc_us-gaap_CommonStockMember_994D4F5428E1BACB7B5B374BA5A8F0F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_ED12F38D6D01D41C22D1374BA5A87210" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9258D3D2027BC715639D374BA5A7F99B" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_ED12F38D6D01D41C22D1374BA5A87210" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ED12F38D6D01D41C22D1374BA5A87210" xlink:to="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ED12F38D6D01D41C22D1374BA5A87210" xlink:to="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_6F4FF38FC1445C99E077374BA5A85D41" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_6F4FF38FC1445C99E077374BA5A85D41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_52A98DA7C6DC849745E1374BA5A8CFA0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:to="loc_us-gaap_CommonStockMember_52A98DA7C6DC849745E1374BA5A8CFA0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_8CE41D045F94DF482DB3374BA5A882DC" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_8CE41D045F94DF482DB3374BA5A882DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_632FF9E5FBAE8B8F71A2374BA5A8FAA8" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:to="loc_us-gaap_RetainedEarningsMember_632FF9E5FBAE8B8F71A2374BA5A8FAA8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_69DBAFE47A233D8909E7374BA5A9D5DC" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7439376BF2F0A5054A00374BA5A8D03C" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_69DBAFE47A233D8909E7374BA5A9D5DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_CF083511F4D0EC5B4AE7374BA5A9919A" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaap_SharesOutstanding_76CB7F8AB5621F43FD76374BA5A905C5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_SharesOutstanding_76CB7F8AB5621F43FD76374BA5A905C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_22D674372D18BC681227374BA5A9E410" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockholdersEquity_22D674372D18BC681227374BA5A9E410" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_325F84F25EE952AF9084374BA5A95A4D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_325F84F25EE952AF9084374BA5A95A4D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_6BD7D5306FEE34C24A75374BA5A9AF92" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_6BD7D5306FEE34C24A75374BA5A9AF92" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_19916DD750CCE7101F9D374BA5A9473D" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_19916DD750CCE7101F9D374BA5A9473D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_F2ED5C4FC3B68D5E99F0374BA5A92F74" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_F2ED5C4FC3B68D5E99F0374BA5A92F74" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_ABF1A8F9056215CD41FF374BA5A9F498" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_ABF1A8F9056215CD41FF374BA5A9F498" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_367F3644E46D34E1CFEE374BA5A932C3" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_367F3644E46D34E1CFEE374BA5A932C3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueOther" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueOther_45122FF942BCEC262785374BA5A9EC65" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueOther_45122FF942BCEC262785374BA5A9EC65" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesOther_CA226ADE376E8D55B761374BA5A9A686" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesOther_CA226ADE376E8D55B761374BA5A9A686" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AdjustmentToAdditionalPaidInCapitalWarrantsAndCommonStockIssuedInConnectionWithConvertibleSecurities" xlink:label="loc_enph_AdjustmentToAdditionalPaidInCapitalWarrantsAndCommonStockIssuedInConnectionWithConvertibleSecurities_558BACD4AC4297EBE05F374BA5A9AF35" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_enph_AdjustmentToAdditionalPaidInCapitalWarrantsAndCommonStockIssuedInConnectionWithConvertibleSecurities_558BACD4AC4297EBE05F374BA5A9AF35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature_AFBD9B47F47336A6D809374BA5A949D0" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature_AFBD9B47F47336A6D809374BA5A949D0" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AdjustmentsToAdditionalPaidInCapitalOtherAccruedPaidInKindInterestConvertibleNotes" xlink:label="loc_enph_AdjustmentsToAdditionalPaidInCapitalOtherAccruedPaidInKindInterestConvertibleNotes_408F34E2844D1AE6E8DE374BA5AAC7CE" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_enph_AdjustmentsToAdditionalPaidInCapitalOtherAccruedPaidInKindInterestConvertibleNotes_408F34E2844D1AE6E8DE374BA5AAC7CE" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_StockIssuedDuringPeriodShareConversionOfConvertiblePreferredStockIntoCommonStock" xlink:label="loc_enph_StockIssuedDuringPeriodShareConversionOfConvertiblePreferredStockIntoCommonStock_6D40D8DCB6CB1954A92D374BA5AA465C" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_enph_StockIssuedDuringPeriodShareConversionOfConvertiblePreferredStockIntoCommonStock_6D40D8DCB6CB1954A92D374BA5AA465C" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_StockIssuedDuringPeriodValueConversionOfConvertiblePreferredStockInToCommonStock" xlink:label="loc_enph_StockIssuedDuringPeriodValueConversionOfConvertiblePreferredStockInToCommonStock_E6D34AB435E6CFE1B5FF374BA5AA83B3" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_enph_StockIssuedDuringPeriodValueConversionOfConvertiblePreferredStockInToCommonStock_E6D34AB435E6CFE1B5FF374BA5AA83B3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_7B8EE20BD6B7A2305AC0374BA5AA354F" xlink:type="locator" />
    <definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_7B8EE20BD6B7A2305AC0374BA5AA354F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_9E643E8F5850470E9B21374BA5AAED0C" xlink:type="locator" />
    <definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_9E643E8F5850470E9B21374BA5AAED0C" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AdjustmentsToAdditionalPaidInCapitalReclassificationOfPreferredStockWarrantLiabilityToAdditionalPaidInCapitalUponIpo" xlink:label="loc_enph_AdjustmentsToAdditionalPaidInCapitalReclassificationOfPreferredStockWarrantLiabilityToAdditionalPaidInCapitalUponIpo_F53338E583DA87F7DFA0374BA5AAFC21" xlink:type="locator" />
    <definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_enph_AdjustmentsToAdditionalPaidInCapitalReclassificationOfPreferredStockWarrantLiabilityToAdditionalPaidInCapitalUponIpo_F53338E583DA87F7DFA0374BA5AAFC21" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_C2687BE68CA3E9D7554D374BA5AAB790" xlink:type="locator" />
    <definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_NetIncomeLoss_C2687BE68CA3E9D7554D374BA5AAB790" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_D04B0E78BA4F6A154A0B374BA5AA59BE" xlink:type="locator" />
    <definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_994A994C7860405AA848374BA5A97ED8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_D04B0E78BA4F6A154A0B374BA5AA59BE" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedStatementOfStockholdersEquityParenthetical" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_E8E0833D84784B61625C213AF0B4FDAB" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_38F354730E2C4B99CA97213AF0B45CC0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_E8E0833D84784B61625C213AF0B4FDAB" xlink:to="loc_us-gaap_StatementTable_38F354730E2C4B99CA97213AF0B45CC0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_FD8A474F6C3C05F0D60D213AF0B443AF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_38F354730E2C4B99CA97213AF0B45CC0" xlink:to="loc_us-gaap_StatementClassOfStockAxis_FD8A474F6C3C05F0D60D213AF0B443AF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_AA4AB9FB43BB5FD2E840213AF0B4B01B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_FD8A474F6C3C05F0D60D213AF0B443AF" xlink:to="loc_us-gaap_ClassOfStockDomain_AA4AB9FB43BB5FD2E840213AF0B4B01B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_AA4AB9FB43BB5FD2E840213AF0B4B01B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_FD8A474F6C3C05F0D60D213AF0B443AF" xlink:to="loc_us-gaap_ClassOfStockDomain_AA4AB9FB43BB5FD2E840213AF0B4B01B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_CAC23EA37F2E563D4E41213AF0B42B76" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_AA4AB9FB43BB5FD2E840213AF0B4B01B" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_CAC23EA37F2E563D4E41213AF0B42B76" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SeriesEPreferredStockMember" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_9666ED9401FEB14F4705213AF0B410F3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConvertiblePreferredStockMember_CAC23EA37F2E563D4E41213AF0B42B76" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_9666ED9401FEB14F4705213AF0B410F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_3CD9B42967CB730855C9213AF0B43315" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_E8E0833D84784B61625C213AF0B4FDAB" xlink:to="loc_us-gaap_SharePrice_3CD9B42967CB730855C9213AF0B43315" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_2A73D2D4B2680706EBCA213AF0B48C89" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_E8E0833D84784B61625C213AF0B4FDAB" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_2A73D2D4B2680706EBCA213AF0B48C89" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_954AFB0B589213B9A1913776FBEE211F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_StatementTable_954AFB0B589213B9A1913776FBEE211F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_0507CD72CE396C71C9FD3776FBEE2197" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_954AFB0B589213B9A1913776FBEE211F" xlink:to="loc_us-gaap_StatementClassOfStockAxis_0507CD72CE396C71C9FD3776FBEE2197" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_0507CD72CE396C71C9FD3776FBEE2197" xlink:to="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_0507CD72CE396C71C9FD3776FBEE2197" xlink:to="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_CD6C5A3F899525C8C5603776FBEE7019" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_CD6C5A3F899525C8C5603776FBEE7019" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_125A141CE32BEC70B5CE3776FBEE25AD" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_DBFEA40A12B6A5133EB83776FBEE8995" xlink:to="loc_us-gaap_CommonStockMember_125A141CE32BEC70B5CE3776FBEE25AD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_BE986CDD07247758DB503776FBEE40D8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_954AFB0B589213B9A1913776FBEE211F" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_BE986CDD07247758DB503776FBEE40D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_BE986CDD07247758DB503776FBEE40D8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_BE986CDD07247758DB503776FBEE40D8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleDebtMember" xlink:label="loc_us-gaap_ConvertibleDebtMember_A8B529FE56D937A0CA923776FBEF24E4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A" xlink:to="loc_us-gaap_ConvertibleDebtMember_A8B529FE56D937A0CA923776FBEF24E4" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_DebtExcludingConvertibleDebtMember" xlink:label="loc_enph_DebtExcludingConvertibleDebtMember_59C9361520CD98FFE7A73776FBEFF35E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_CA19142DD3241D7250553776FBEEDB3A" xlink:to="loc_enph_DebtExcludingConvertibleDebtMember_59C9361520CD98FFE7A73776FBEFF35E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6B5674EDF7A1F4D5EA103776FBEFDDD0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_954AFB0B589213B9A1913776FBEE211F" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6B5674EDF7A1F4D5EA103776FBEFDDD0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_154BFB9943DE1B57BE623776FBEFF662_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6B5674EDF7A1F4D5EA103776FBEFDDD0" xlink:to="loc_us-gaap_EquityComponentDomain_154BFB9943DE1B57BE623776FBEFF662_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_154BFB9943DE1B57BE623776FBEFF662" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6B5674EDF7A1F4D5EA103776FBEFDDD0" xlink:to="loc_us-gaap_EquityComponentDomain_154BFB9943DE1B57BE623776FBEFF662" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_5104E0CCE836AB4EBF053776FBEF38AB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_154BFB9943DE1B57BE623776FBEFF662" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_5104E0CCE836AB4EBF053776FBEF38AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1BCD32649F29182F09E23776FBEFB1E3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1BCD32649F29182F09E23776FBEFB1E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_C8F6EF388A61A363ADBE3776FBEF1E7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1BCD32649F29182F09E23776FBEFB1E3" xlink:to="loc_us-gaap_NetIncomeLoss_C8F6EF388A61A363ADBE3776FBEF1E7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1BCD32649F29182F09E23776FBEFB1E3" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_3069EC3EBBAEC627D3003776FBEF177A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_3069EC3EBBAEC627D3003776FBEF177A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_88184E192281B435244C3776FBEF6527" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_88184E192281B435244C3776FBEF6527" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GainsLossesOnSalesOfOtherAssets" xlink:label="loc_us-gaap_GainsLossesOnSalesOfOtherAssets_1E09C9131B0A40EB678E3776FBEF064C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_GainsLossesOnSalesOfOtherAssets_1E09C9131B0A40EB678E3776FBEF064C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_D85ADE8F67B2A48C06893776FBF017A5" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_D85ADE8F67B2A48C06893776FBF017A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_C221F09BC41A0039267A3776FBF02C75" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_ShareBasedCompensation_C221F09BC41A0039267A3776FBF02C75" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_2DA5095A93F7D66C14A43776FBF0A808" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_2DA5095A93F7D66C14A43776FBF0A808" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingAssetsAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36309E493E4E96FCDD9B3776FBEFB5F9" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_F386C4B7886D5C8AADA83776FBF04414" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_F386C4B7886D5C8AADA83776FBF04414" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_892E5A17F73F0B9A9E583776FBF042F9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_892E5A17F73F0B9A9E583776FBF042F9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_56E14679D9BC6164AE063776FBF0AA79" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_56E14679D9BC6164AE063776FBF0AA79" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_F0571CE03A41AD22D4363776FBF0BB54" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_F0571CE03A41AD22D4363776FBF0BB54" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_CFF508CCD5C67401384E3776FBF09632" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_80B8A4F51F7F9136F2603776FBF0E3E0" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_CFF508CCD5C67401384E3776FBF09632" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_297247689B3A25A583863776FBF0DDDC" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1BCD32649F29182F09E23776FBEFB1E3" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_297247689B3A25A583863776FBF0DDDC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E61308CB961C0C5032283776FBF0B21F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E61308CB961C0C5032283776FBF0B21F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_07ABB5BF6E5EDBC80EE43776FBF0F215" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E61308CB961C0C5032283776FBF0B21F" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_07ABB5BF6E5EDBC80EE43776FBF0F215" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_DA07431B208325EA63843776FBF09DE3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E61308CB961C0C5032283776FBF0B21F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_DA07431B208325EA63843776FBF09DE3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock_AED992F6416278CEBBAB3776FBF123D3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock_AED992F6416278CEBBAB3776FBF123D3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_DF4B1AFAF5EB586510EF3776FBF17F26" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_DF4B1AFAF5EB586510EF3776FBF17F26" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfNotesPayable" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfNotesPayable_4FBAF3803BEF7373CBA33776FBF1A097" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfNotesPayable_4FBAF3803BEF7373CBA33776FBF1A097" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_4E145908BEBD9BA65C053776FBF10821" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_4E145908BEBD9BA65C053776FBF10821" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfPrivatePlacement_0ECE329A093306235A733776FBF1B82C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfPrivatePlacement_0ECE329A093306235A733776FBF1B82C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:label="loc_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_FA500A6BCCA1686D27173776FBF1C070" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_FA500A6BCCA1686D27173776FBF1C070" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_B3EA3BE8ECF63FB179A13776FBF1E6E9" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_B3EA3BE8ECF63FB179A13776FBF1E6E9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_2370BF92116406B851973776FBF117CD" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_2370BF92116406B851973776FBF117CD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromStockPlans" xlink:label="loc_us-gaap_ProceedsFromStockPlans_CF7492A55DEF71A4D6013776FBF1CFB0" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromStockPlans_CF7492A55DEF71A4D6013776FBF1CFB0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_E3E12DDC356BA314C3933776FBF19865" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_E3E12DDC356BA314C3933776FBF19865" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_F97A1BD5C5F0B0960BE13776FBF165E4" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_89EE44AD84995732E9573776FBF19D3E" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_F97A1BD5C5F0B0960BE13776FBF165E4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_0E01F9D36E0B4D3C2DF43776FBF1B096" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_0E01F9D36E0B4D3C2DF43776FBF1B096" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_BEF565A71DAC1FF4F2C63776FBF14F05" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_BEF565A71DAC1FF4F2C63776FBF14F05" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D6ECB052FF09D957DB53776FBF1DA40" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D6ECB052FF09D957DB53776FBF1DA40" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_FC1928E565753AEC47D03776FBF27171" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_FC1928E565753AEC47D03776FBF27171" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_A9AB6C7BE11CE3BFCB6D3776FBF215C6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_FC1928E565753AEC47D03776FBF27171" xlink:to="loc_us-gaap_InterestPaid_A9AB6C7BE11CE3BFCB6D3776FBF215C6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:label="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_FA53BDAE230D2B4A09463776FBEFB652" xlink:to="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalLeaseObligationsIncurred" xlink:label="loc_us-gaap_CapitalLeaseObligationsIncurred_ACCEAD3E69306C7255473776FBF2C2A1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:to="loc_us-gaap_CapitalLeaseObligationsIncurred_ACCEAD3E69306C7255473776FBF2C2A1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_6542D4A8AADFB40690F73776FBF291CB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_6542D4A8AADFB40690F73776FBF291CB" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_OfferingCostsNotYetPaid" xlink:label="loc_enph_OfferingCostsNotYetPaid_194F667C46FABE9069E33776FBF2CD9F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:to="loc_enph_OfferingCostsNotYetPaid_194F667C46FABE9069E33776FBF2CD9F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_BCF845724DFE8D0AF7BD3776FBF25329" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_BCF845724DFE8D0AF7BD3776FBF25329" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ReclassificationOfPreferredStockWarrantLiability" xlink:label="loc_enph_ReclassificationOfPreferredStockWarrantLiability_674A4AD986E35BE2452F3776FBF253B3" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_934FA9821ABEC99E975E3776FBF2B5B8" xlink:to="loc_enph_ReclassificationOfPreferredStockWarrantLiability_674A4AD986E35BE2452F3776FBF253B3" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedStatementsOfComprehensiveLoss" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_A3690333CCC988C40016372F467CFE84" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_3AA3E0CAC3FD81A44EF7372F467A10E4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_A3690333CCC988C40016372F467CFE84" xlink:to="loc_us-gaap_StatementTable_3AA3E0CAC3FD81A44EF7372F467A10E4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_0FA80A5061CAE70B8CF7372F467C1876" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3AA3E0CAC3FD81A44EF7372F467A10E4" xlink:to="loc_us-gaap_StatementScenarioAxis_0FA80A5061CAE70B8CF7372F467C1876" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_F5737270C64932A16738372F467C83DE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_0FA80A5061CAE70B8CF7372F467C1876" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_F5737270C64932A16738372F467C83DE_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_F5737270C64932A16738372F467C83DE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_0FA80A5061CAE70B8CF7372F467C1876" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_F5737270C64932A16738372F467C83DE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_B49930C7A142DC6364AE372F467D2660" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A3690333CCC988C40016372F467CFE84" xlink:to="loc_us-gaap_NetIncomeLoss_B49930C7A142DC6364AE372F467D2660" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_267BCFD495515FA40CFD372F467FFF48" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A3690333CCC988C40016372F467CFE84" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_267BCFD495515FA40CFD372F467FFF48" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_118AD284118C4EE51232372F467FC339" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_267BCFD495515FA40CFD372F467FFF48" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_118AD284118C4EE51232372F467FC339" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_7B2E671070E24C92B556372F467F1344" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_267BCFD495515FA40CFD372F467FFF48" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_7B2E671070E24C92B556372F467F1344" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_0F1B8CFF676F7D640E83372F467F064C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A3690333CCC988C40016372F467CFE84" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_0F1B8CFF676F7D640E83372F467F064C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConsolidatedStatementsOfOperations" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_5FF1B6AB3592A9F741304939083BE22C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_StatementTable_5FF1B6AB3592A9F741304939083BE22C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_2757284FB4582B98D95A4939083B2F60" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5FF1B6AB3592A9F741304939083BE22C" xlink:to="loc_us-gaap_StatementScenarioAxis_2757284FB4582B98D95A4939083B2F60" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_7432E4C0998EC5524E234939083B3BDF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_2757284FB4582B98D95A4939083B2F60" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_7432E4C0998EC5524E234939083B3BDF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_7432E4C0998EC5524E234939083B3BDF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_2757284FB4582B98D95A4939083B2F60" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_7432E4C0998EC5524E234939083B3BDF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_083EF03715385DA556E74939083C5B7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_SalesRevenueNet_083EF03715385DA556E74939083C5B7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaap_CostOfRevenue_D6FCC003E490422737A84939083E2D1B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_CostOfRevenue_D6FCC003E490422737A84939083E2D1B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_EF47AF4C8672FDD8F9104939083ED82C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_GrossProfit_EF47AF4C8672FDD8F9104939083ED82C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_CBFC6F4256E416A188864939083E144D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_CBFC6F4256E416A188864939083E144D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_E12755D29D8D8FA20B3C4939083E22A3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:to="loc_us-gaap_SellingAndMarketingExpense_E12755D29D8D8FA20B3C4939083E22A3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_0C8D6D25254A314F0EBF4939083E03ED" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_0C8D6D25254A314F0EBF4939083E03ED" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_6EAA61B802336BC0D5204939083ECCCD" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_0FE2CEF48EC1E686844C4939083EFF99" xlink:to="loc_us-gaap_OperatingExpenses_6EAA61B802336BC0D5204939083ECCCD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_3ECCE8449CE3B260C57A4939083EB63E" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_3ECCE8449CE3B260C57A4939083EB63E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_0D0F51BD4CE339D506824939083E483C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:to="loc_us-gaap_InvestmentIncomeInterest_0D0F51BD4CE339D506824939083E483C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_403CE8E21146378CF2F94939083EF857" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:to="loc_us-gaap_InterestExpense_403CE8E21146378CF2F94939083EF857" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_C2B55CC02EF160D0B3BD4939083E1680" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_C2B55CC02EF160D0B3BD4939083E1680" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_42DB2D45736B7C83C8C34939083F6F8F" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_5667E904EF0C778B33044939083E0A95" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_42DB2D45736B7C83C8C34939083F6F8F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8A67C7406A17F07A13B34939083F5C6A" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8A67C7406A17F07A13B34939083F5C6A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_3DA85EE760763089B2B04939083FC750" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_3DA85EE760763089B2B04939083FC750" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_9DF871DFD4C363CF69E54939083F9448" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_NetIncomeLoss_9DF871DFD4C363CF69E54939083F9448" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare_F0DA4886CA368504C8024939083FD583" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare_F0DA4886CA368504C8024939083FD583" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_C41A7855C3C21193F75F4939083FA6D5" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86D060C5B912D5C568494939083BC060" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_C41A7855C3C21193F75F4939083FA6D5" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/ConvertibleFacilityNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_18E4B17EF516045229AF1D6B6FA8635E" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_D545CC415DBBE91A98331D6B6FA84554" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_18E4B17EF516045229AF1D6B6FA8635E" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_D545CC415DBBE91A98331D6B6FA84554" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_8059E4EB5575BB948FE11D6B6FA88171" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D545CC415DBBE91A98331D6B6FA84554" xlink:to="loc_us-gaap_CreditFacilityAxis_8059E4EB5575BB948FE11D6B6FA88171" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_D0F71E8AD0C8E11125CD1D6B6FA8022C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_8059E4EB5575BB948FE11D6B6FA88171" xlink:to="loc_us-gaap_CreditFacilityDomain_D0F71E8AD0C8E11125CD1D6B6FA8022C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_D0F71E8AD0C8E11125CD1D6B6FA8022C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_8059E4EB5575BB948FE11D6B6FA88171" xlink:to="loc_us-gaap_CreditFacilityDomain_D0F71E8AD0C8E11125CD1D6B6FA8022C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_2DB36CAEF7D7FAF909841D6B6FA85F26" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_D0F71E8AD0C8E11125CD1D6B6FA8022C" xlink:to="loc_us-gaap_SecuredDebtMember_2DB36CAEF7D7FAF909841D6B6FA85F26" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleSubordinatedDebtMember" xlink:label="loc_us-gaap_ConvertibleSubordinatedDebtMember_AD50A094F239720CC0601D6B6FA87D4F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SecuredDebtMember_2DB36CAEF7D7FAF909841D6B6FA85F26" xlink:to="loc_us-gaap_ConvertibleSubordinatedDebtMember_AD50A094F239720CC0601D6B6FA87D4F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4518863A69F4808F63211D6B6FA84A8F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D545CC415DBBE91A98331D6B6FA84554" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4518863A69F4808F63211D6B6FA84A8F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_BECEBCC081D0B8092ADB1D6B6FA8C41F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4518863A69F4808F63211D6B6FA84A8F" xlink:to="loc_us-gaap_ClassOfStockDomain_BECEBCC081D0B8092ADB1D6B6FA8C41F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_BECEBCC081D0B8092ADB1D6B6FA8C41F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4518863A69F4808F63211D6B6FA84A8F" xlink:to="loc_us-gaap_ClassOfStockDomain_BECEBCC081D0B8092ADB1D6B6FA8C41F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_30FEA168F001F093C2D51D6B6FA8D0D8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_BECEBCC081D0B8092ADB1D6B6FA8C41F" xlink:to="loc_us-gaap_CommonStockMember_30FEA168F001F093C2D51D6B6FA8D0D8" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmendmentAxis" xlink:label="loc_enph_AmendmentAxis_2B4CDF160622BE50DBEA1D6B6FA825B8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D545CC415DBBE91A98331D6B6FA84554" xlink:to="loc_enph_AmendmentAxis_2B4CDF160622BE50DBEA1D6B6FA825B8" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmendmentDomain" xlink:label="loc_enph_AmendmentDomain_5D3949C5F51FD6E10F281D6B6FA89312_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_enph_AmendmentAxis_2B4CDF160622BE50DBEA1D6B6FA825B8" xlink:to="loc_enph_AmendmentDomain_5D3949C5F51FD6E10F281D6B6FA89312_default" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmendmentDomain" xlink:label="loc_enph_AmendmentDomain_5D3949C5F51FD6E10F281D6B6FA89312" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_enph_AmendmentAxis_2B4CDF160622BE50DBEA1D6B6FA825B8" xlink:to="loc_enph_AmendmentDomain_5D3949C5F51FD6E10F281D6B6FA89312" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmendmentToDebtAgreementMember" xlink:label="loc_enph_AmendmentToDebtAgreementMember_0F460515B6E8164621EB1D6B6FA808DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AmendmentDomain_5D3949C5F51FD6E10F281D6B6FA89312" xlink:to="loc_enph_AmendmentToDebtAgreementMember_0F460515B6E8164621EB1D6B6FA808DF" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ConvertibleFacilityTextualAbstract" xlink:label="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_18E4B17EF516045229AF1D6B6FA8635E" xlink:to="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_9418D8A1E5F4D5AD85D11D6B6FA85C17" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_9418D8A1E5F4D5AD85D11D6B6FA85C17" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_44BF49C82FDB22A2A1A61D6B6FA94D57" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_44BF49C82FDB22A2A1A61D6B6FA94D57" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_370E50EFD45E2E41C1031D6B6FA94179" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_370E50EFD45E2E41C1031D6B6FA94179" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_9F8CCB537FA6AC009DDF1D6B6FA9FB4E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_9F8CCB537FA6AC009DDF1D6B6FA9FB4E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_F5B6547489140F54774D1D6B6FA93D59" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_SharePrice_F5B6547489140F54774D1D6B6FA93D59" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_A7C8247B495938E898C51D6B6FA91E8F" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_A7C8247B495938E898C51D6B6FA91E8F" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ConvertibleSecuritiesCommonStockContractualTerm" xlink:label="loc_enph_ConvertibleSecuritiesCommonStockContractualTerm_684D8778D3ECD57ACBDE1D6B6FA95FE3" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_enph_ConvertibleSecuritiesCommonStockContractualTerm_684D8778D3ECD57ACBDE1D6B6FA95FE3" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_DebtDiscountsAndDebtIssuanceCost" xlink:label="loc_enph_DebtDiscountsAndDebtIssuanceCost_A50A24115D01A408EF121D6B6FA96782" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_enph_DebtDiscountsAndDebtIssuanceCost_A50A24115D01A408EF121D6B6FA96782" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="loc_us-gaap_InterestExpenseDebt_A5634E1DE02185656E621D6B6FA9BED0" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ConvertibleFacilityTextualAbstract_A7045EF289008E91932C1D6B6FA88E41" xlink:to="loc_us-gaap_InterestExpenseDebt_A5634E1DE02185656E621D6B6FA9BED0" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/FairValueMeasurementsHeirarchyDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F4283E24CE99A85898F43776FBBF5859" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_B12EE2CDCDFC478DD99C3776FBBE3E14" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F4283E24CE99A85898F43776FBBF5859" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_B12EE2CDCDFC478DD99C3776FBBE3E14" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_17327DE89D53F9A1A90E3776FBBEAB52" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_B12EE2CDCDFC478DD99C3776FBBE3E14" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_17327DE89D53F9A1A90E3776FBBEAB52" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_BDD0FAF86BC6AD902A9A3776FBBE3E48_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_17327DE89D53F9A1A90E3776FBBEAB52" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_BDD0FAF86BC6AD902A9A3776FBBE3E48_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_BDD0FAF86BC6AD902A9A3776FBBE3E48" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_17327DE89D53F9A1A90E3776FBBEAB52" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_BDD0FAF86BC6AD902A9A3776FBBE3E48" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_6FA78EBB4961A14DBEF53776FBBE71CA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_BDD0FAF86BC6AD902A9A3776FBBE3E48" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_6FA78EBB4961A14DBEF53776FBBE71CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6030B0B4330E069D34B43776FBBF083F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_B12EE2CDCDFC478DD99C3776FBBE3E14" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6030B0B4330E069D34B43776FBBF083F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6030B0B4330E069D34B43776FBBF083F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6030B0B4330E069D34B43776FBBF083F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_D2B8CD65F5402EA1BED73776FBBF35AF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_D2B8CD65F5402EA1BED73776FBBF35AF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_80D3AFB19AE89E2D2AA23776FBBFE78A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9D3263540FDFB87555183776FBBF4A08" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_80D3AFB19AE89E2D2AA23776FBBFE78A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9B8239A553870FA806D23776FBBFFB93" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F4283E24CE99A85898F43776FBBF5859" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9B8239A553870FA806D23776FBBFFB93" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MandatorilyRedeemablePreferredStockFairValueDisclosure" xlink:label="loc_us-gaap_MandatorilyRedeemablePreferredStockFairValueDisclosure_263FA0BB2547C221A2073776FBBF0C24" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9B8239A553870FA806D23776FBBFFB93" xlink:to="loc_us-gaap_MandatorilyRedeemablePreferredStockFairValueDisclosure_263FA0BB2547C221A2073776FBBF0C24" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_28455E2404BBCF8A0ACC3776FBBF8833" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9B8239A553870FA806D23776FBBFFB93" xlink:to="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_28455E2404BBCF8A0ACC3776FBBF8833" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_43955CA300ADDCB70CB73776FBBF2AE8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9B8239A553870FA806D23776FBBFFB93" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_43955CA300ADDCB70CB73776FBBF2AE8" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/FairValueMeasurementsSummaryOfOpenForeignCurrencyForwardContractsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_4759F358FE9A350A7DC9369EAAE849E8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_B90F459FCB62C3B1AE10369EAAE86247" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_4759F358FE9A350A7DC9369EAAE849E8" xlink:to="loc_us-gaap_DerivativeTable_B90F459FCB62C3B1AE10369EAAE86247" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeByNatureAxis" xlink:label="loc_us-gaap_DerivativeByNatureAxis_5C22E3020AF022ACB123369EAAE82DBA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B90F459FCB62C3B1AE10369EAAE86247" xlink:to="loc_us-gaap_DerivativeByNatureAxis_5C22E3020AF022ACB123369EAAE82DBA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="loc_us-gaap_DerivativeNameDomain_5B83C0198B241C7A91CE369EAAE808AA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeByNatureAxis_5C22E3020AF022ACB123369EAAE82DBA" xlink:to="loc_us-gaap_DerivativeNameDomain_5B83C0198B241C7A91CE369EAAE808AA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="loc_us-gaap_DerivativeNameDomain_5B83C0198B241C7A91CE369EAAE808AA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeByNatureAxis_5C22E3020AF022ACB123369EAAE82DBA" xlink:to="loc_us-gaap_DerivativeNameDomain_5B83C0198B241C7A91CE369EAAE808AA" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_JanuaryFifteenTwoThousandThirteenMember" xlink:label="loc_enph_JanuaryFifteenTwoThousandThirteenMember_DE5E327AFE6ACD2AA936369EAAE89BB0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeNameDomain_5B83C0198B241C7A91CE369EAAE808AA" xlink:to="loc_enph_JanuaryFifteenTwoThousandThirteenMember_DE5E327AFE6ACD2AA936369EAAE89BB0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract_336FA05F9500CC4814E0369EAAE8BF02" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_4759F358FE9A350A7DC9369EAAE849E8" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract_336FA05F9500CC4814E0369EAAE8BF02" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotionalAmountOfForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments" xlink:label="loc_us-gaap_NotionalAmountOfForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments_F7F20900DE960ACA5829369EAAE8BAEA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract_336FA05F9500CC4814E0369EAAE8BF02" xlink:to="loc_us-gaap_NotionalAmountOfForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments_F7F20900DE960ACA5829369EAAE8BAEA" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsMarketValue" xlink:label="loc_enph_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsMarketValue_74EB4CC3FDEDCFDF62AE369EAAE90A0E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract_336FA05F9500CC4814E0369EAAE8BF02" xlink:to="loc_enph_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsMarketValue_74EB4CC3FDEDCFDF62AE369EAAE90A0E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:label="loc_us-gaap_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue_5D234CFC83E5A0527102369EAAE94A05" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract_336FA05F9500CC4814E0369EAAE8BF02" xlink:to="loc_us-gaap_ForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue_5D234CFC83E5A0527102369EAAE94A05" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/GeographicInformationLongLivedAssetsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B46BEBC4B071F4EC1A50218B0FC619A1" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_E7C7769FD4CBA629EF85218B0FC50569" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B46BEBC4B071F4EC1A50218B0FC619A1" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_E7C7769FD4CBA629EF85218B0FC50569" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_057EF770A44ADAB0E7AF218B0FC5BCFF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_E7C7769FD4CBA629EF85218B0FC50569" xlink:to="loc_us-gaap_StatementGeographicalAxis_057EF770A44ADAB0E7AF218B0FC5BCFF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_057EF770A44ADAB0E7AF218B0FC5BCFF" xlink:to="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_057EF770A44ADAB0E7AF218B0FC5BCFF" xlink:to="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd#country_US" xlink:label="loc_country_US_2722376E49272E51020C218B0FC5C0EF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D" xlink:to="loc_country_US_2722376E49272E51020C218B0FC5C0EF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd#country_CN" xlink:label="loc_country_CN_1C0F51146AA26DF9EC81218B0FC5CE73" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D" xlink:to="loc_country_CN_1C0F51146AA26DF9EC81218B0FC5CE73" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_OtherCountryMember" xlink:label="loc_enph_OtherCountryMember_3AFD4BFA6C44B05D2551218B0FC59C92" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_F6017413E4D188E860D8218B0FC5D74D" xlink:to="loc_enph_OtherCountryMember_3AFD4BFA6C44B05D2551218B0FC59C92" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LongLivedAssetsAbstract" xlink:label="loc_enph_LongLivedAssetsAbstract_931019C23AAD847BBAC7218B0FC6E099" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B46BEBC4B071F4EC1A50218B0FC619A1" xlink:to="loc_enph_LongLivedAssetsAbstract_931019C23AAD847BBAC7218B0FC6E099" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="loc_us-gaap_NoncurrentAssets_15FEAA7BC002A736CA57218B0FC6EE3D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongLivedAssetsAbstract_931019C23AAD847BBAC7218B0FC6E099" xlink:to="loc_us-gaap_NoncurrentAssets_15FEAA7BC002A736CA57218B0FC6EE3D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/GeographicInformationNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_77E33E453D6AB95E7FE23691A095B53C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_81699617088C713D92033691A094176B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_77E33E453D6AB95E7FE23691A095B53C" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_81699617088C713D92033691A094176B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_7F18F1E86B0C8B2D1BD5369235D8B8D4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_81699617088C713D92033691A094176B" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_7F18F1E86B0C8B2D1BD5369235D8B8D4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_E19436479ACC674A6B993692373DD70B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_7F18F1E86B0C8B2D1BD5369235D8B8D4" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_E19436479ACC674A6B993692373DD70B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_E19436479ACC674A6B993692373DD70B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_7F18F1E86B0C8B2D1BD5369235D8B8D4" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_E19436479ACC674A6B993692373DD70B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeographicConcentrationRiskMember" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember_754868F04224DFF380D636928A3787C7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_E19436479ACC674A6B993692373DD70B" xlink:to="loc_us-gaap_GeographicConcentrationRiskMember_754868F04224DFF380D636928A3787C7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_52A71D231FBC13B7243A3691F1BC79F6" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_81699617088C713D92033691A094176B" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_52A71D231FBC13B7243A3691F1BC79F6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_B08C5479500812EAF6ED3691F308163D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_52A71D231FBC13B7243A3691F1BC79F6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_B08C5479500812EAF6ED3691F308163D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_B08C5479500812EAF6ED3691F308163D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_52A71D231FBC13B7243A3691F1BC79F6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_B08C5479500812EAF6ED3691F308163D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueSegmentMember" xlink:label="loc_us-gaap_SalesRevenueSegmentMember_AB5CF634A6DDC4BEC9353694625C6493" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_B08C5479500812EAF6ED3691F308163D" xlink:to="loc_us-gaap_SalesRevenueSegmentMember_AB5CF634A6DDC4BEC9353694625C6493" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_2A5AD1555BA92ECEB0503691A095D6B2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_81699617088C713D92033691A094176B" xlink:to="loc_us-gaap_StatementGeographicalAxis_2A5AD1555BA92ECEB0503691A095D6B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_7918AADB1801A4D8D2773691A095743F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_2A5AD1555BA92ECEB0503691A095D6B2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_7918AADB1801A4D8D2773691A095743F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_7918AADB1801A4D8D2773691A095743F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_2A5AD1555BA92ECEB0503691A095D6B2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_7918AADB1801A4D8D2773691A095743F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd#country_CA" xlink:label="loc_country_CA_F9094690985F819A81943691A0956762" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_7918AADB1801A4D8D2773691A095743F" xlink:to="loc_country_CA_F9094690985F819A81943691A0956762" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RevenueNetPercentage" xlink:label="loc_enph_RevenueNetPercentage_0B6E05CE64E7F707B8763691A5140932" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_77E33E453D6AB95E7FE23691A095B53C" xlink:to="loc_enph_RevenueNetPercentage_0B6E05CE64E7F707B8763691A5140932" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/GeographicInformationNetRevenuesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B0A48C0BE42616EE1D6C21D2651DAE37" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_B57C8F72CE002A7506AC21D2651D148A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B0A48C0BE42616EE1D6C21D2651DAE37" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_B57C8F72CE002A7506AC21D2651D148A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_B031944905D8C214EF0121D2651D11BB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_B57C8F72CE002A7506AC21D2651D148A" xlink:to="loc_us-gaap_StatementGeographicalAxis_B031944905D8C214EF0121D2651D11BB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_B031944905D8C214EF0121D2651D11BB" xlink:to="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_B031944905D8C214EF0121D2651D11BB" xlink:to="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd#country_US" xlink:label="loc_country_US_F7F7F37498533EAEDFDD21D2651DDAAA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78" xlink:to="loc_country_US_F7F7F37498533EAEDFDD21D2651DDAAA" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_InternationalMember" xlink:label="loc_enph_InternationalMember_BF97E392357F11E5356821D2651DBD02" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_4C6DFEDA9E6B134909C221D2651DDA78" xlink:to="loc_enph_InternationalMember_BF97E392357F11E5356821D2651DBD02" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_0FF2FB2AC02641304B5921E0D4D8D7DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_B0A48C0BE42616EE1D6C21D2651DAE37" xlink:to="loc_us-gaap_SalesRevenueNet_0FF2FB2AC02641304B5921E0D4D8D7DF" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/IncomeTaxesEffectiveIncomeTaxReconciliationDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <loc xlink:href="enph-20121231.xsd#enph_IncomeTaxesLineItems" xlink:label="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:type="locator" />
    <loc xlink:href="enph-20121231.xsd#enph_IncomeTaxesTable" xlink:label="loc_enph_IncomeTaxesTable_C70A5A9A80B71159C6D622087B0626D4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_enph_IncomeTaxesTable_C70A5A9A80B71159C6D622087B0626D4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_53678E1E368D4369367B22087B0A5C68" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_enph_IncomeTaxesTable_C70A5A9A80B71159C6D622087B0626D4" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_53678E1E368D4369367B22087B0A5C68" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_53678E1E368D4369367B22087B0A5C68" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_53678E1E368D4369367B22087B0A5C68" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InternalRevenueServiceIRSMember" xlink:label="loc_us-gaap_InternalRevenueServiceIRSMember_4E5ADA9DA57778B0F8EB22087B0AC599" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72" xlink:to="loc_us-gaap_InternalRevenueServiceIRSMember_4E5ADA9DA57778B0F8EB22087B0AC599" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_2DE4BA10034DF7E4DBA022087B0AB1A5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019190CE36EF200B909222087B0A6E72" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_2DE4BA10034DF7E4DBA022087B0AB1A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd#stpr_CA" xlink:label="loc_stpr_CA_CA61E9D2933D40F6059F22087B0A57B4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StateAndLocalJurisdictionMember_2DE4BA10034DF7E4DBA022087B0AB1A5" xlink:to="loc_stpr_CA_CA61E9D2933D40F6059F22087B0A57B4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_3EBC28BB4539061C56182208BB450E02" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_3EBC28BB4539061C56182208BB450E02" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentForeignTaxExpenseBenefit_B829D51A6272AFB897E82208BB45B41E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_CurrentForeignTaxExpenseBenefit_B829D51A6272AFB897E82208BB45B41E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_A7D300175D2D7BD8C9732208BB46F22F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_A7D300175D2D7BD8C9732208BB46F22F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaap_OperatingLossCarryforwards_22DA361738B5E10B54022208BB468518" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_OperatingLossCarryforwards_22DA361738B5E10B54022208BB468518" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_AA96D02507591A7C90592208BB4663D8" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_AA96D02507591A7C90592208BB4663D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_FBB132A7423D9D8EB6772208BB460D06" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_FBB132A7423D9D8EB6772208BB460D06" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions_01F278133C393F4E44452208BB4621CD" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions_01F278133C393F4E44452208BB4621CD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_8240096604C842773C342208BB46AAF2" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_IncomeTaxesLineItems_E4EB093268D4F6F212672208BB3B01B1" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_8240096604C842773C342208BB46AAF2" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/Inventory" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/LongTermDebtNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_59275BB195146491328221B1064A0A9F" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59275BB195146491328221B1064A0A9F" xlink:to="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_70041342D9F35D3409C221B106438D87" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_70041342D9F35D3409C221B106438D87" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_70041342D9F35D3409C221B106438D87" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_70041342D9F35D3409C221B106438D87" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_D11FC0B318D2C2018EAD21B10643585D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9" xlink:to="loc_us-gaap_SecuredDebtMember_D11FC0B318D2C2018EAD21B10643585D" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EquipmentFinancingFacilityMember" xlink:label="loc_enph_EquipmentFinancingFacilityMember_1E2D80127336789799EB21B1064380B4" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9" xlink:to="loc_enph_EquipmentFinancingFacilityMember_1E2D80127336789799EB21B1064380B4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_6CDC65731A6B3B94944721B10644F076" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_602FCCA3DEAD1A2E0AAA21B1064388D9" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_6CDC65731A6B3B94944721B10644F076" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_10082F7359C8DB793F4C21B106448621" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_10082F7359C8DB793F4C21B106448621" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_10082F7359C8DB793F4C21B106448621" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_10082F7359C8DB793F4C21B106448621" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_HorizonTechnologyFinanceCorporationMember" xlink:label="loc_enph_HorizonTechnologyFinanceCorporationMember_6F546023897EBF22187821B1064471DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:to="loc_enph_HorizonTechnologyFinanceCorporationMember_6F546023897EBF22187821B1064471DF" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_HerculesTechnologyGrowthCapitalIncMember" xlink:label="loc_enph_HerculesTechnologyGrowthCapitalIncMember_D5700DA0124661FD577821B106444A2E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:to="loc_enph_HerculesTechnologyGrowthCapitalIncMember_D5700DA0124661FD577821B106444A2E" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_BridgeBankNationalAssociationAndComericaMember" xlink:label="loc_enph_BridgeBankNationalAssociationAndComericaMember_8B9EA66165120A808A6B21B106440636" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:to="loc_enph_BridgeBankNationalAssociationAndComericaMember_8B9EA66165120A808A6B21B106440636" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_WellsFargoBankMember" xlink:label="loc_enph_WellsFargoBankMember_A5BD9803202FA7E8EB8C21B106440AC6" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_340401127581D4989D4F21B10644A506" xlink:to="loc_enph_WellsFargoBankMember_A5BD9803202FA7E8EB8C21B106440AC6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_E133A32AF8794FD233FC21B106440286" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:to="loc_us-gaap_RangeAxis_E133A32AF8794FD233FC21B106440286" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_E133A32AF8794FD233FC21B106440286" xlink:to="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_E133A32AF8794FD233FC21B106440286" xlink:to="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_44A5F4571238B555894421B10644E5E3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C" xlink:to="loc_us-gaap_MinimumMember_44A5F4571238B555894421B10644E5E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_F9B0AFA169E1E1B6FA1E21B106447912" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3FCE093D5D5C68B4A34F21B10644518C" xlink:to="loc_us-gaap_MaximumMember_F9B0AFA169E1E1B6FA1E21B106447912" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_VariableRateAxis" xlink:label="loc_enph_VariableRateAxis_B2FB6C6F6FCD941D880B21B10644B105" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_A27F28AD6EA94B18511E21B106433330" xlink:to="loc_enph_VariableRateAxis_B2FB6C6F6FCD941D880B21B10644B105" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_VariableRateDomain" xlink:label="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_enph_VariableRateAxis_B2FB6C6F6FCD941D880B21B10644B105" xlink:to="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9_default" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_VariableRateDomain" xlink:label="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_enph_VariableRateAxis_B2FB6C6F6FCD941D880B21B10644B105" xlink:to="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_PrimeRateMember" xlink:label="loc_enph_PrimeRateMember_2F626C6EC7D0C9A614AB21B1064484B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9" xlink:to="loc_enph_PrimeRateMember_2F626C6EC7D0C9A614AB21B1064484B2" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LondonInterbankOfferedRateLiborOrBaseRateMember" xlink:label="loc_enph_LondonInterbankOfferedRateLiborOrBaseRateMember_65C2ABBDE57A707126E221B1064A8A27" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_VariableRateDomain_3A26460BEE0B5545FB7721B1064476A9" xlink:to="loc_enph_LondonInterbankOfferedRateLiborOrBaseRateMember_65C2ABBDE57A707126E221B1064A8A27" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LongTermDebtTextualAbstract" xlink:label="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59275BB195146491328221B1064A0A9F" xlink:to="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_5D28BC2CD8E368F251AA21B1064ADAB8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_5D28BC2CD8E368F251AA21B1064ADAB8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_3A8F7DC820F22B95AAC521B1064AD3E0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_3A8F7DC820F22B95AAC521B1064AD3E0" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmountOfLiquidityRequiredForDebtCompliance" xlink:label="loc_enph_AmountOfLiquidityRequiredForDebtCompliance_A7BFA15D37D999E3734E21B1064A5595" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_enph_AmountOfLiquidityRequiredForDebtCompliance_A7BFA15D37D999E3734E21B1064A5595" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AmountOfUndrawnCreditForDebtCompliance" xlink:label="loc_enph_AmountOfUndrawnCreditForDebtCompliance_C1BD5A6201EAA03CD1F121B1064A5132" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_enph_AmountOfUndrawnCreditForDebtCompliance_C1BD5A6201EAA03CD1F121B1064A5132" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_F3623E98E1908AB983A921B1064ADD90" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_F3623E98E1908AB983A921B1064ADD90" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentIncreaseAdditionalBorrowings" xlink:label="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_F2E9B3AE6AF96760939721B1064AB63B" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_F2E9B3AE6AF96760939721B1064AB63B" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ProjectedEbitdaAndRevenueToMeetAdditionalTermLoansAchievementPercentage" xlink:label="loc_enph_ProjectedEbitdaAndRevenueToMeetAdditionalTermLoansAchievementPercentage_140CDCAD115454991AB321B1064A34A8" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_enph_ProjectedEbitdaAndRevenueToMeetAdditionalTermLoansAchievementPercentage_140CDCAD115454991AB321B1064A34A8" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_LineOfCreditFacilityExtensionTerm" xlink:label="loc_enph_LineOfCreditFacilityExtensionTerm_E75284EDD5CE5B85228221B1064A42A2" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_enph_LineOfCreditFacilityExtensionTerm_E75284EDD5CE5B85228221B1064A42A2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfSubordinatedDebt" xlink:label="loc_us-gaap_RepaymentsOfSubordinatedDebt_1AE42990BE302FFDE28621B1064A3E3E" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_RepaymentsOfSubordinatedDebt_1AE42990BE302FFDE28621B1064A3E3E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_0F89ADF2BC2D20E4D4E021B1064A901F" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_0F89ADF2BC2D20E4D4E021B1064A901F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_15B9A8F086D00EEE947721B1064A58FC" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_15B9A8F086D00EEE947721B1064A58FC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_06D5BBEBE10A0096638E21B1064AAF0E" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_06D5BBEBE10A0096638E21B1064AAF0E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_EDE82371E900AEC2777F21B1064BBDEA" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_EDE82371E900AEC2777F21B1064BBDEA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_B1C4CA56FF92246D6EE321B1064BB353" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_B1C4CA56FF92246D6EE321B1064BB353" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_A5C1230A358F86939BA021B1064B86B6" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_LongTermDebtTextualAbstract_15F622AD7DD63A2037C921B1064A987F" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_A5C1230A358F86939BA021B1064B86B6" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/LongTermDebtScheduleOfDebtDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_4B35AE20709843BBE3893776FBB672FB" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_08D603DCC5C35CD95D023776FBB655A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4B35AE20709843BBE3893776FBB672FB" xlink:to="loc_us-gaap_DebtInstrumentTable_08D603DCC5C35CD95D023776FBB655A4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_A966281CF91F33DF92663776FBB6044F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_08D603DCC5C35CD95D023776FBB655A4" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_A966281CF91F33DF92663776FBB6044F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A966281CF91F33DF92663776FBB6044F" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A966281CF91F33DF92663776FBB6044F" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_2E222678571195CA339C3776FBB6B9E2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74" xlink:to="loc_us-gaap_SecuredDebtMember_2E222678571195CA339C3776FBB6B9E2" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EquipmentFinancingFacilityMember" xlink:label="loc_enph_EquipmentFinancingFacilityMember_78B75EBA408A3C3D7B123776FBB66C35" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_770FD9F4EBCCA7CB3E043776FBB6BB74" xlink:to="loc_enph_EquipmentFinancingFacilityMember_78B75EBA408A3C3D7B123776FBB66C35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtCurrentAndNoncurrentAbstract" xlink:label="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4B35AE20709843BBE3893776FBB672FB" xlink:to="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_4F6C209B243D991EC7903776FBB67A00" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:to="loc_us-gaap_LongTermDebt_4F6C209B243D991EC7903776FBB67A00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_7B627254FBE629778F913776FBB6A208" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:to="loc_us-gaap_LongTermDebtCurrent_7B627254FBE629778F913776FBB6A208" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_497C7198F9E6B8C131873776FBB60259" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_497C7198F9E6B8C131873776FBB60259" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_138EDA189D0DBCE34AA93776FBB6C402" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_26EB051C0945E3AB48B43776FBB6646B" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_138EDA189D0DBCE34AA93776FBB6C402" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/LongTermDebtScheduleOfMaturitiesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/LongTermDebtTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/NetLossPerShareAttributableToCommonStockholdersNarrativeDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/NetLossPerShareAttributableToCommonStockholdersPotentialCommonSharesOutstandingExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_2EB961F0074681352D6321D9E9499367" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_30803D7AA90FFA4DCF1021D9E948C898" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_2EB961F0074681352D6321D9E9499367" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_30803D7AA90FFA4DCF1021D9E948C898" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8F8285DC619F7CCDEC5621D9E949D8C1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_30803D7AA90FFA4DCF1021D9E948C898" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8F8285DC619F7CCDEC5621D9E949D8C1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8F8285DC619F7CCDEC5621D9E949D8C1" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8F8285DC619F7CCDEC5621D9E949D8C1" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_37159E3C8DB938D2DC1621D9E949C35D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_37159E3C8DB938D2DC1621D9E949C35D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_BC8E1D1350AE1D72ADF421D9E949446B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_StockOptionsMember_BC8E1D1350AE1D72ADF421D9E949446B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_CD6FCD92BBC8F311587221D9E94937FA" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_CD6FCD92BBC8F311587221D9E94937FA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_BE33CE3B818514E2EEE121D9E949A341" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_EmployeeStockOptionMember_BE33CE3B818514E2EEE121D9E949A341" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_4CA1146D4DE7F180A10321D9E949F783" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_4CA1146D4DE7F180A10321D9E949F783" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaap_WarrantMember_3548F21558C74CE9E03621D9E9499F3B" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_us-gaap_WarrantMember_3548F21558C74CE9E03621D9E9499F3B" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_WarrantConvertibleCommonStockMember" xlink:label="loc_enph_WarrantConvertibleCommonStockMember_D672C6AB0ED07B3116DC21D9E9499302" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_74A38BA7F1F983DBF9DB21D9E949060F" xlink:to="loc_enph_WarrantConvertibleCommonStockMember_D672C6AB0ED07B3116DC21D9E9499302" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AntidilutiveSecuritiesAbstract" xlink:label="loc_enph_AntidilutiveSecuritiesAbstract_E7D7877F2EC198DC3A6621D9E949871E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_2EB961F0074681352D6321D9E9499367" xlink:to="loc_enph_AntidilutiveSecuritiesAbstract_E7D7877F2EC198DC3A6621D9E949871E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_D3332924F20921C45B5521D9E949B4A6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AntidilutiveSecuritiesAbstract_E7D7877F2EC198DC3A6621D9E949871E" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_D3332924F20921C45B5521D9E949B4A6" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/OrganizationAndDescriptionOfBusiness" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/PropertyAndEquipmentNetNarrativeDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0C64266C34F52DF51A6E1D6B6FD5CC2F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0C64266C34F52DF51A6E1D6B6FD5CC2F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5F789BB9D4BE3461BCA41D6B6FD5BDA3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0C64266C34F52DF51A6E1D6B6FD5CC2F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5F789BB9D4BE3461BCA41D6B6FD5BDA3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5F789BB9D4BE3461BCA41D6B6FD5BDA3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5F789BB9D4BE3461BCA41D6B6FD5BDA3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_429CEE8E7FD7DBE199B21D6B6FD5667D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_429CEE8E7FD7DBE199B21D6B6FD5667D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_E11723A04DA1A26D6B361D6B6FD591BF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_E11723A04DA1A26D6B361D6B6FD591BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaap_ComputerEquipmentMember_E23A8ACDAC41D70D99D91D6B6FD5B859" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_ComputerEquipmentMember_E23A8ACDAC41D70D99D91D6B6FD5B859" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SoftwareDevelopmentMember" xlink:label="loc_us-gaap_SoftwareDevelopmentMember_1DF47EF3A3EF4F9A1C791D6B6FD50917" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_SoftwareDevelopmentMember_1DF47EF3A3EF4F9A1C791D6B6FD50917" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_2723869F67123605FFF91D6B6FD557A5" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_2723869F67123605FFF91D6B6FD557A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="loc_us-gaap_ConstructionInProgressMember_FAEDABB5ACDEF0A3EFBE1D6B6FD57749" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_21ABC22277C936B7EEC11D6B6FD5F81F" xlink:to="loc_us-gaap_ConstructionInProgressMember_FAEDABB5ACDEF0A3EFBE1D6B6FD57749" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_5413DDDE7D4BB7F3A0741D6B6FD50CDA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0C64266C34F52DF51A6E1D6B6FD5CC2F" xlink:to="loc_us-gaap_RangeAxis_5413DDDE7D4BB7F3A0741D6B6FD50CDA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_5413DDDE7D4BB7F3A0741D6B6FD50CDA" xlink:to="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_5413DDDE7D4BB7F3A0741D6B6FD50CDA" xlink:to="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_73B69024B9590107E1381D6B6FD6CE60" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F" xlink:to="loc_us-gaap_MinimumMember_73B69024B9590107E1381D6B6FD6CE60" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_BB3108EB54AD349515191D6B6FD6022F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_85E0297070CEA40AF8F21D6B6FD5776F" xlink:to="loc_us-gaap_MaximumMember_BB3108EB54AD349515191D6B6FD6022F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_D2BC718B382477236A681D6B6FD639A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_D2BC718B382477236A681D6B6FD639A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_66003AA106C70418980E1D6B6FD67FB8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_66003AA106C70418980E1D6B6FD67FB8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_F6F236EC05385D6872EF1D6B6FD691C9" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_F6F236EC05385D6872EF1D6B6FD691C9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_CFA08A99F0BAB44988251D6B6FD6C2E1" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_52965CA5E99FF802D0751D6B6FD60693" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_CFA08A99F0BAB44988251D6B6FD6C2E1" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/QuarterlyFinancialInformation" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/QuarterlyFinancialInformationDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/QuarterlyFinancialInformationTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_9B4E4B51016359F9C19D1D97A461E142" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_47904C5DD8CD834A0BD91D9756E29E47" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9B4E4B51016359F9C19D1D97A461E142" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_47904C5DD8CD834A0BD91D9756E29E47" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_30DEF46BFF22CB67E99D1D96D6CC532F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_47904C5DD8CD834A0BD91D9756E29E47" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_30DEF46BFF22CB67E99D1D96D6CC532F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3BB07EA524B30505D34D1D96D6CF7568_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_30DEF46BFF22CB67E99D1D96D6CC532F" xlink:to="loc_us-gaap_RelatedPartyDomain_3BB07EA524B30505D34D1D96D6CF7568_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3BB07EA524B30505D34D1D96D6CF7568" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_30DEF46BFF22CB67E99D1D96D6CC532F" xlink:to="loc_us-gaap_RelatedPartyDomain_3BB07EA524B30505D34D1D96D6CF7568" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestorMember" xlink:label="loc_us-gaap_InvestorMember_19BDADD5146262331A3F1D99D4848684" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3BB07EA524B30505D34D1D96D6CF7568" xlink:to="loc_us-gaap_InvestorMember_19BDADD5146262331A3F1D99D4848684" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_KpcbHoldingsIncMember" xlink:label="loc_enph_KpcbHoldingsIncMember_FC50A00053AA81FF95AD1D9AC1DC3F2F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestorMember_19BDADD5146262331A3F1D99D4848684" xlink:to="loc_enph_KpcbHoldingsIncMember_FC50A00053AA81FF95AD1D9AC1DC3F2F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_DEE188B0CA6B2E38E7951D6B6F2D266B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9B4E4B51016359F9C19D1D97A461E142" xlink:to="loc_us-gaap_RevenueFromRelatedParties_DEE188B0CA6B2E38E7951D6B6F2D266B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1686E6BFA297A3193656B290EBF0F10A" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3AD9F0824B02CE90270AB290EBF02DF9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1686E6BFA297A3193656B290EBF0F10A" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3AD9F0824B02CE90270AB290EBF02DF9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_D11CA2EF05A4D2B2477DB290EBF0FFCE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3AD9F0824B02CE90270AB290EBF02DF9" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_D11CA2EF05A4D2B2477DB290EBF0FFCE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_D11CA2EF05A4D2B2477DB290EBF0FFCE" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_D11CA2EF05A4D2B2477DB290EBF0FFCE" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_30070768732FAEBE58A2B290EBF0FD7F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:to="loc_us-gaap_CostOfSalesMember_30070768732FAEBE58A2B290EBF0FD7F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_E0DD22BED2E489832C02B290EBF0FF6F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_E0DD22BED2E489832C02B290EBF0FF6F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_4671243CF632E6D53360B290EBF0D7AA" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_4671243CF632E6D53360B290EBF0D7AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_8F936CC38EAB46B1A6A1B290EBF03EEF" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_92F519FF7A503802A108B290EBF0F1BC" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_8F936CC38EAB46B1A6A1B290EBF03EEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_44AA272BC4E6EB8A1897B290EBF082D9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1686E6BFA297A3193656B290EBF0F10A" xlink:to="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_44AA272BC4E6EB8A1897B290EBF082D9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_0F2CE935D4C502A27BB9B290EBF05F4F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_44AA272BC4E6EB8A1897B290EBF082D9" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_0F2CE935D4C502A27BB9B290EBF05F4F" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationExpenseByAwardTypeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_4E4CC6CE1E5D25D447773AF3DA37AA2B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_B0425752FE55BD2844E63AF3DA37ABBD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_4E4CC6CE1E5D25D447773AF3DA37AA2B" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_B0425752FE55BD2844E63AF3DA37ABBD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_3575D6E678B17AF7946B3AF3DA37E67D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_B0425752FE55BD2844E63AF3DA37ABBD" xlink:to="loc_us-gaap_AwardTypeAxis_3575D6E678B17AF7946B3AF3DA37E67D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_3575D6E678B17AF7946B3AF3DA37E67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_3575D6E678B17AF7946B3AF3DA37E67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_EAEBE1973E6AB925F92F3AF3DA375EDE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_EAEBE1973E6AB925F92F3AF3DA375EDE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_EE5F1084264AC4624EB13AF3DA37F9FE" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D7FA5D3EF361C3B0CBDB3AF3DA3758FC" xlink:to="loc_us-gaap_EmployeeStockMember_EE5F1084264AC4624EB13AF3DA37F9FE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_2608617CF138BC39683E3AF3DA378F9A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_4E4CC6CE1E5D25D447773AF3DA37AA2B" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_2608617CF138BC39683E3AF3DA378F9A" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_DCE1689481D353B066DE374BA4D1541F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_DCE1689481D353B066DE374BA4D1541F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_CF1C1505CC4058A27886374BA4D17BB0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_DCE1689481D353B066DE374BA4D1541F" xlink:to="loc_us-gaap_PlanNameAxis_CF1C1505CC4058A27886374BA4D17BB0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_CF1C1505CC4058A27886374BA4D17BB0" xlink:to="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_CF1C1505CC4058A27886374BA4D17BB0" xlink:to="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_TwoThousandSixPlanMember" xlink:label="loc_enph_TwoThousandSixPlanMember_F02F3BB052C0174682C0374BA4D1FCCE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D" xlink:to="loc_enph_TwoThousandSixPlanMember_F02F3BB052C0174682C0374BA4D1FCCE" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_TwoThousandAndElevenPlanMember" xlink:label="loc_enph_TwoThousandAndElevenPlanMember_AD94FC87DC709F6D43AE374BA4D10C42" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D" xlink:to="loc_enph_TwoThousandAndElevenPlanMember_AD94FC87DC709F6D43AE374BA4D10C42" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockPurchasePlanEsppMember" xlink:label="loc_enph_EmployeeStockPurchasePlanEsppMember_8FD684AAE95B56298C70374BA4D18FE3" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_C715AB36A20D4C64D209374BA4D1438D" xlink:to="loc_enph_EmployeeStockPurchasePlanEsppMember_8FD684AAE95B56298C70374BA4D18FE3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_190C95EE367BA9D0198C374BA4D11CDB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_DCE1689481D353B066DE374BA4D1541F" xlink:to="loc_us-gaap_AwardTypeAxis_190C95EE367BA9D0198C374BA4D11CDB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4873BDCF0BD903EDD8EC374BA4D1724E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_190C95EE367BA9D0198C374BA4D11CDB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4873BDCF0BD903EDD8EC374BA4D1724E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4873BDCF0BD903EDD8EC374BA4D1724E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_190C95EE367BA9D0198C374BA4D11CDB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4873BDCF0BD903EDD8EC374BA4D1724E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_C6A6338C087E5B68FF74374BA4D21BE7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4873BDCF0BD903EDD8EC374BA4D1724E" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_C6A6338C087E5B68FF74374BA4D21BE7" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AwardDateAxis" xlink:label="loc_enph_AwardDateAxis_357285B5630E83B483B2374BA4D2A386" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_DCE1689481D353B066DE374BA4D1541F" xlink:to="loc_enph_AwardDateAxis_357285B5630E83B483B2374BA4D2A386" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AwardDateDomain" xlink:label="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_enph_AwardDateAxis_357285B5630E83B483B2374BA4D2A386" xlink:to="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE_default" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AwardDateDomain" xlink:label="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_enph_AwardDateAxis_357285B5630E83B483B2374BA4D2A386" xlink:to="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_BeforeAugustMember" xlink:label="loc_enph_BeforeAugustMember_20BCB7884CAEDC5DDC99374BA4D2FC11" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE" xlink:to="loc_enph_BeforeAugustMember_20BCB7884CAEDC5DDC99374BA4D2FC11" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_AfterAugustMember" xlink:label="loc_enph_AfterAugustMember_02BA05D304F2E423BA01374BA4D20FE8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AwardDateDomain_0BB241BB597E54EA6271374BA4D2D1EE" xlink:to="loc_enph_AfterAugustMember_02BA05D304F2E423BA01374BA4D20FE8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_B2BBD50787E4021CDBDD374BA4D28E31" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_B2BBD50787E4021CDBDD374BA4D28E31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_304C2B58A1DB311B4828374BA4D21992" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_304C2B58A1DB311B4828374BA4D21992" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_DF00B2F220265433B577374BA4D2D792" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_DF00B2F220265433B577374BA4D2D792" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_6D940CCC5A8ABE59F454374BA4D2DA13" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_6D940CCC5A8ABE59F454374BA4D2DA13" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_993C2CDB9E5D677ECDC1374BA4D2F4BC" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_993C2CDB9E5D677ECDC1374BA4D2F4BC" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationInYears" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationInYears_71F3790D9A10327F75F4374BA4D22216" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationInYears_71F3790D9A10327F75F4374BA4D22216" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_IncreaseInCommonStockSharesReservedForFutureIssuancePercentage" xlink:label="loc_enph_IncreaseInCommonStockSharesReservedForFutureIssuancePercentage_6662A8E94B60F46801C3374BA4D2F958" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_IncreaseInCommonStockSharesReservedForFutureIssuancePercentage_6662A8E94B60F46801C3374BA4D2F958" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_E8597FDBCB438CBBE3BF374BA4D2DEB9" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_E8597FDBCB438CBBE3BF374BA4D2DEB9" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEvergreenShares" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEvergreenShares_E4C4AD7AEED005E551FF374BA4D28AFD" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEvergreenShares_E4C4AD7AEED005E551FF374BA4D28AFD" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_OfferingPeriodMaximum" xlink:label="loc_enph_OfferingPeriodMaximum_75252A29B43F05437524374BA4D29277" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_OfferingPeriodMaximum_75252A29B43F05437524374BA4D29277" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockPurchasePlanNumberOfInterimPurchasePeriods" xlink:label="loc_enph_EmployeeStockPurchasePlanNumberOfInterimPurchasePeriods_2B154FD8226B360E480D374BA4D30814" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_EmployeeStockPurchasePlanNumberOfInterimPurchasePeriods_2B154FD8226B360E480D374BA4D30814" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_GeneralDurationOfEmployeeStockPurchasePlan" xlink:label="loc_enph_GeneralDurationOfEmployeeStockPurchasePlan_4E3FDED1D2B29BAD779B374BA4D389BD" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_GeneralDurationOfEmployeeStockPurchasePlan_4E3FDED1D2B29BAD779B374BA4D389BD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_8A5FF6B8F9A1DBE2DA7C374BA4D3C395" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_8A5FF6B8F9A1DBE2DA7C374BA4D3C395" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_39983CCB2173EC8BBB2F374BA4D38C24" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_39983CCB2173EC8BBB2F374BA4D38C24" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardLookBackFeaturePeriod" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardLookBackFeaturePeriod_6C6E42AC6604C0829698374BA4D39B23" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardLookBackFeaturePeriod_6C6E42AC6604C0829698374BA4D39B23" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockPurchasePlanAdditionalExpenseTriggedByResetFeaturePeriodForRecognition" xlink:label="loc_enph_EmployeeStockPurchasePlanAdditionalExpenseTriggedByResetFeaturePeriodForRecognition_7C2BA85553D4689E3150374BA4D32B2A" xlink:type="locator" />
    <definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_EmployeeStockPurchasePlanAdditionalExpenseTriggedByResetFeaturePeriodForRecognition_7C2BA85553D4689E3150374BA4D32B2A" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_IrsLimitationForEmployeesRightToAcquireClassCommonStockUnderEspp" xlink:label="loc_enph_IrsLimitationForEmployeesRightToAcquireClassCommonStockUnderEspp_8808472A1037652A3067374BA4D39DE1" xlink:type="locator" />
    <definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_IrsLimitationForEmployeesRightToAcquireClassCommonStockUnderEspp_8808472A1037652A3067374BA4D39DE1" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockPurchasePlanOfferingPeriod" xlink:label="loc_enph_EmployeeStockPurchasePlanOfferingPeriod_D3732920E57FBB7A78AE374BA4D37F8B" xlink:type="locator" />
    <definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_EmployeeStockPurchasePlanOfferingPeriod_D3732920E57FBB7A78AE374BA4D37F8B" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EmployeeStockPurchasePlanNumberOfPurchasePeriods" xlink:label="loc_enph_EmployeeStockPurchasePlanNumberOfPurchasePeriods_DB8DE34B344FD2E744A0374BA4D364B2" xlink:type="locator" />
    <definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_EmployeeStockPurchasePlanNumberOfPurchasePeriods_DB8DE34B344FD2E744A0374BA4D364B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_E89FDD52904D7C680E7E374BA4D3E324" xlink:type="locator" />
    <definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_E89FDD52904D7C680E7E374BA4D3E324" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_94041D0383D550B4EF0F375629AE521B" xlink:type="locator" />
    <definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_94041D0383D550B4EF0F375629AE521B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_8B28534D74B372F25D06374BA4D3A25F" xlink:type="locator" />
    <definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_8B28534D74B372F25D06374BA4D3A25F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice_729E1BE1C3EE3F272F7B374BA4D33166" xlink:type="locator" />
    <definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice_729E1BE1C3EE3F272F7B374BA4D33166" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1_55948504CEDE4FFD0063374BA4D3A225" xlink:type="locator" />
    <definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1_55948504CEDE4FFD0063374BA4D3A225" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_D7ED988B63F0CDE8491F374BA4D37C5F" xlink:type="locator" />
    <definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_D7ED988B63F0CDE8491F374BA4D37C5F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_2D395DDCC7CD8E46C7B7374EBF08FC79" xlink:type="locator" />
    <definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_2D395DDCC7CD8E46C7B7374EBF08FC79" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingBasisForDeterminingAggregateIntrinsicValueCompanysSharePricePerShare" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingBasisForDeterminingAggregateIntrinsicValueCompanysSharePricePerShare_79C58F86477A336548C3374BA4D3378B" xlink:type="locator" />
    <definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingBasisForDeterminingAggregateIntrinsicValueCompanysSharePricePerShare_79C58F86477A336548C3374BA4D3378B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_B6EF4138BDC90AA1EBA8374BA4D318E3" xlink:type="locator" />
    <definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_B6EF4138BDC90AA1EBA8374BA4D318E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_AA1CA639A2620BAC52CB374BA4D3F1B8" xlink:type="locator" />
    <definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_AA1CA639A2620BAC52CB374BA4D3F1B8" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueValue" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueValue_A0CF7175F161C1249B45374BA4D4A603" xlink:type="locator" />
    <definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueValue_A0CF7175F161C1249B45374BA4D4A603" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_F0C0161ACED46B86D388374BA4D40570" xlink:type="locator" />
    <definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_F0C0161ACED46B86D388374BA4D40570" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_5C851ADC560D5A13BC2C374BA4D4A42A" xlink:type="locator" />
    <definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5C16CF1B542D0435C409374BA4D2B577" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_5C851ADC560D5A13BC2C374BA4D4A42A" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationRangeOfExercisePriceDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C5E5CD442B0B3FE789C821D2656251E9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C5E5CD442B0B3FE789C821D2656251E9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_4CA634CEC86C26F53BFF21D2656251DD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C5E5CD442B0B3FE789C821D2656251E9" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_4CA634CEC86C26F53BFF21D2656251DD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_4CA634CEC86C26F53BFF21D2656251DD" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_4CA634CEC86C26F53BFF21D2656251DD" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeOneMember" xlink:label="loc_enph_RangeOneMember_8C319E9F597DA233208F21D265637697" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeOneMember_8C319E9F597DA233208F21D265637697" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeTwoMember" xlink:label="loc_enph_RangeTwoMember_A43FFA710EB43C79A49721D265631613" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeTwoMember_A43FFA710EB43C79A49721D265631613" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeThreeMember" xlink:label="loc_enph_RangeThreeMember_EB4BEA34BAB201A1093C21D26563EF15" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeThreeMember_EB4BEA34BAB201A1093C21D26563EF15" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeFourMember" xlink:label="loc_enph_RangeFourMember_41DEDF491EF30447AB8C21D265632E6D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeFourMember_41DEDF491EF30447AB8C21D265632E6D" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeFiveMember" xlink:label="loc_enph_RangeFiveMember_5F946990322FDFE24BCC21D26563FF0A" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeFiveMember_5F946990322FDFE24BCC21D26563FF0A" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeSixMember" xlink:label="loc_enph_RangeSixMember_D597D6545723A705BEC221D26563C99A" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeSixMember_D597D6545723A705BEC221D26563C99A" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RangeSevenMember" xlink:label="loc_enph_RangeSevenMember_B0C572A730037C000D0321D26563C129" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_72371C748B3A985FF94B21D26562A6FA" xlink:to="loc_enph_RangeSevenMember_B0C572A730037C000D0321D26563C129" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_6CE0A53C062A36F8C1B621D265630303" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_6CE0A53C062A36F8C1B621D265630303" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_CE431A2D9B34AAF7F4AE21D26563F564" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_CE431A2D9B34AAF7F4AE21D26563F564" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_87F27B9170551225E4A921D26563A9FB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_87F27B9170551225E4A921D26563A9FB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_5FD1139545A7A7C4068B21D26563FAC0" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_5FD1139545A7A7C4068B21D26563FAC0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_EA8924253230BDB0285C21D26563ED67" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_EA8924253230BDB0285C21D26563ED67" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_0C05C11C71539EA7226821D2656384C8" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_0C05C11C71539EA7226821D2656384C8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_29209126A878AD5F15D621D2656471F4" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_30950ACA0CDC58484B6F21D265636BA6" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_29209126A878AD5F15D621D2656471F4" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95632270CDAE7CC2DD2B1C6D4D17A4FC" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EC64A4747A85C18E2DC11C6D4D17FD1E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95632270CDAE7CC2DD2B1C6D4D17A4FC" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EC64A4747A85C18E2DC11C6D4D17FD1E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_775985160CEA092B74351C6D4D17E072" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EC64A4747A85C18E2DC11C6D4D17FD1E" xlink:to="loc_us-gaap_AwardTypeAxis_775985160CEA092B74351C6D4D17E072" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_A314F382D5A0C97DBD201C6D4D174498_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_775985160CEA092B74351C6D4D17E072" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_A314F382D5A0C97DBD201C6D4D174498_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_A314F382D5A0C97DBD201C6D4D174498" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_775985160CEA092B74351C6D4D17E072" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_A314F382D5A0C97DBD201C6D4D174498" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_D8107BC242310F98DC4E1C6D4D1780AA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_A314F382D5A0C97DBD201C6D4D174498" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_D8107BC242310F98DC4E1C6D4D1780AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95632270CDAE7CC2DD2B1C6D4D17A4FC" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_D0D085D22DB124FD9CAF1C6D4D18D6C8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_D0D085D22DB124FD9CAF1C6D4D18D6C8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0053D5F699B17BD03D531C6D4D1833B3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0053D5F699B17BD03D531C6D4D1833B3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_5B6B7EF926FC6E3101F01C6D4D18FF27" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_5B6B7EF926FC6E3101F01C6D4D18FF27" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_27A1861F3BB7564532D51C6D4D18F5EE" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_BC75888B539B623D39DE1C6D4D17FEF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_27A1861F3BB7564532D51C6D4D18F5EE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95632270CDAE7CC2DD2B1C6D4D17A4FC" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_9AFB20FDBD4B5C0DEF6A1C6D4D18B361" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_9AFB20FDBD4B5C0DEF6A1C6D4D18B361" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_F75327677C9F19151C5B1C6D4D18361B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_F75327677C9F19151C5B1C6D4D18361B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_691021A42B16EF97604F1C6D4D18A085" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_691021A42B16EF97604F1C6D4D18A085" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_5464675485BB3DC4DBEC1C6D4D1824A7" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_57886AF7C545C909303F1C6D4D18993E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_5464675485BB3DC4DBEC1C6D4D1824A7" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7D29A069E0433DAD5634369E74BE0246" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7D29A069E0433DAD5634369E74BE0246" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_D5BC6E5AA48A4B8A6609369E74BCDC74" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_D5BC6E5AA48A4B8A6609369E74BCDC74" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_682967147B5E6B7174D6369E74BC636F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_D5BC6E5AA48A4B8A6609369E74BCDC74" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_682967147B5E6B7174D6369E74BC636F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_682967147B5E6B7174D6369E74BC636F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_D5BC6E5AA48A4B8A6609369E74BCDC74" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_682967147B5E6B7174D6369E74BC636F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_9B5E7BEB46E77F73DC85369E74BD9944" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_D5BC6E5AA48A4B8A6609369E74BCDC74" xlink:to="loc_us-gaap_StockOptionsMember_9B5E7BEB46E77F73DC85369E74BD9944" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_8D84E706EAED98CBA421369E74BDF895" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:to="loc_us-gaap_PlanNameAxis_8D84E706EAED98CBA421369E74BDF895" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_629E2E8B55DEA37CA25A369E74BDA9C5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_8D84E706EAED98CBA421369E74BDF895" xlink:to="loc_us-gaap_PlanNameDomain_629E2E8B55DEA37CA25A369E74BDA9C5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_629E2E8B55DEA37CA25A369E74BDA9C5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_8D84E706EAED98CBA421369E74BDF895" xlink:to="loc_us-gaap_PlanNameDomain_629E2E8B55DEA37CA25A369E74BDA9C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_EEF7187F8EBEC39C0209369E74BDC9E1" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:to="loc_us-gaap_AwardTypeAxis_EEF7187F8EBEC39C0209369E74BDC9E1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7286C8B6ACAE3B38237A369E74BD6CBF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_EEF7187F8EBEC39C0209369E74BDC9E1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7286C8B6ACAE3B38237A369E74BD6CBF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7286C8B6ACAE3B38237A369E74BD6CBF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_EEF7187F8EBEC39C0209369E74BDC9E1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7286C8B6ACAE3B38237A369E74BD6CBF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_54033880C84581551AEF369E74BE1A00" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:to="loc_us-gaap_StatementClassOfStockAxis_54033880C84581551AEF369E74BE1A00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_6E3B8BFE4DFA1C4B9063369E74BE5E1A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_54033880C84581551AEF369E74BE1A00" xlink:to="loc_us-gaap_ClassOfStockDomain_6E3B8BFE4DFA1C4B9063369E74BE5E1A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_6E3B8BFE4DFA1C4B9063369E74BE5E1A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_54033880C84581551AEF369E74BE1A00" xlink:to="loc_us-gaap_ClassOfStockDomain_6E3B8BFE4DFA1C4B9063369E74BE5E1A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_E51718E8CE8773525E1E369E74BEF09A" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EE2196F434D669A5DA22369E74BC8C39" xlink:to="loc_us-gaap_RangeAxis_E51718E8CE8773525E1E369E74BEF09A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_F4DF800F419A97219C40369E74BE742D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_E51718E8CE8773525E1E369E74BEF09A" xlink:to="loc_us-gaap_RangeMember_F4DF800F419A97219C40369E74BE742D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_F4DF800F419A97219C40369E74BE742D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_E51718E8CE8773525E1E369E74BEF09A" xlink:to="loc_us-gaap_RangeMember_F4DF800F419A97219C40369E74BE742D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F1A3281164A202EAE51BB290EBD44D88" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F63FA4ABD6B1F5AD7E30B290EBD4C561" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F1A3281164A202EAE51BB290EBD44D88" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F63FA4ABD6B1F5AD7E30B290EBD4C561" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_04A66123FBABB90220CFB290EBD423A8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F63FA4ABD6B1F5AD7E30B290EBD4C561" xlink:to="loc_us-gaap_AwardTypeAxis_04A66123FBABB90220CFB290EBD423A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_84D0158D9FA1D1076738B290EBD43CEF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_04A66123FBABB90220CFB290EBD423A8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_84D0158D9FA1D1076738B290EBD43CEF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_84D0158D9FA1D1076738B290EBD43CEF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_04A66123FBABB90220CFB290EBD423A8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_84D0158D9FA1D1076738B290EBD43CEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_20D3923C78D80EF3939FB290EBD4D492" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_84D0158D9FA1D1076738B290EBD43CEF" xlink:to="loc_us-gaap_StockOptionsMember_20D3923C78D80EF3939FB290EBD4D492" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F1A3281164A202EAE51BB290EBD44D88" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_FB6E71CAE73C66EAB9D4B290EBD4C574" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_FB6E71CAE73C66EAB9D4B290EBD4C574" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_02B0B1E05D892B89EBADB290EBDA35B7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_02B0B1E05D892B89EBADB290EBDA35B7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_30BEC8E4043B61F17EFBB290EBDA8B08" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_30BEC8E4043B61F17EFBB290EBDA8B08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_F8C82DEBB392BB03927AB290EBDA8A1F" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_F8C82DEBB392BB03927AB290EBDA8A1F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_C88F979AAFD8CA60359DB290EBDA7671" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_38CCFB8D1A646A54EC06B290EBD42962" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_C88F979AAFD8CA60359DB290EBDA7671" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockholdersEquityAndWarrantsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_DE7B368ED4DBF4BC0CD235F458DC0E21" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_AAA36F982FD54F1998C835F458D7B1E8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_DE7B368ED4DBF4BC0CD235F458DC0E21" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_AAA36F982FD54F1998C835F458D7B1E8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_E88D9AA3D48176B4654235F458D7A118" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_AAA36F982FD54F1998C835F458D7B1E8" xlink:to="loc_us-gaap_StatementClassOfStockAxis_E88D9AA3D48176B4654235F458D7A118" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_CD582439B20C6547AA1735F458D743DB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_E88D9AA3D48176B4654235F458D7A118" xlink:to="loc_us-gaap_ClassOfStockDomain_CD582439B20C6547AA1735F458D743DB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_CD582439B20C6547AA1735F458D743DB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_E88D9AA3D48176B4654235F458D7A118" xlink:to="loc_us-gaap_ClassOfStockDomain_CD582439B20C6547AA1735F458D743DB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_F02DB1F697C1C78FFE7835F458D73D7D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_CD582439B20C6547AA1735F458D743DB" xlink:to="loc_us-gaap_CommonStockMember_F02DB1F697C1C78FFE7835F458D73D7D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_F0763A96C905E71D136035F458D773B1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_AAA36F982FD54F1998C835F458D7B1E8" xlink:to="loc_us-gaap_RangeAxis_F0763A96C905E71D136035F458D773B1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_F0763A96C905E71D136035F458D773B1" xlink:to="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_F0763A96C905E71D136035F458D773B1" xlink:to="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_44D686B430DD8562FCE835F458DC0F02" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9" xlink:to="loc_us-gaap_MinimumMember_44D686B430DD8562FCE835F458DC0F02" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_86D8490B5402861D864535F458DC3AA2" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_FEEACEE4EEF85B066B2935F458D7ABA9" xlink:to="loc_us-gaap_MaximumMember_86D8490B5402861D864535F458DC3AA2" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_StockholdersEquityTextualAbstract" xlink:label="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_DE7B368ED4DBF4BC0CD235F458DC0E21" xlink:to="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_375C667F6223323E2F3735F458DC30C3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_375C667F6223323E2F3735F458DC30C3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConversionOfStockSharesConverted1" xlink:label="loc_us-gaap_ConversionOfStockSharesConverted1_955128F7D57562ADDCF735F93D0CB846" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:to="loc_us-gaap_ConversionOfStockSharesConverted1_955128F7D57562ADDCF735F93D0CB846" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_F8EE9EB6CA33B82F386235F458DDA4E8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_F8EE9EB6CA33B82F386235F458DDA4E8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_BE7B6D4DF6C8ECBEBDF135F458DD6AD4" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_StockholdersEquityTextualAbstract_62051CA9E785C814175035F458DCAE9E" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_BE7B6D4DF6C8ECBEBDF135F458DD6AD4" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockholdersEquityAndWarrantsSummaryOfChangesInConvertibleStockWarrantLiabilityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_5EB0DB1E5FACA5E1E02C3AF3DA58873D" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_D5406A3D9C1C7708D7AA3AF3DA576847" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_5EB0DB1E5FACA5E1E02C3AF3DA58873D" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_D5406A3D9C1C7708D7AA3AF3DA576847" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4CE97BDCF12DB086CD2A3AF3DA577A87" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_D5406A3D9C1C7708D7AA3AF3DA576847" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4CE97BDCF12DB086CD2A3AF3DA577A87" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_52DA734BC57E74FCB5993AF3DA572683_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4CE97BDCF12DB086CD2A3AF3DA577A87" xlink:to="loc_us-gaap_ClassOfStockDomain_52DA734BC57E74FCB5993AF3DA572683_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_52DA734BC57E74FCB5993AF3DA572683" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4CE97BDCF12DB086CD2A3AF3DA577A87" xlink:to="loc_us-gaap_ClassOfStockDomain_52DA734BC57E74FCB5993AF3DA572683" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_7EF0F351B51CBD83F63E3AF3DA57360F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_52DA734BC57E74FCB5993AF3DA572683" xlink:to="loc_us-gaap_PreferredStockMember_7EF0F351B51CBD83F63E3AF3DA57360F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SeriesEPreferredStockMember" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_87D93525C8BF1A1E99B33AF3DA577FAD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PreferredStockMember_7EF0F351B51CBD83F63E3AF3DA57360F" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_87D93525C8BF1A1E99B33AF3DA577FAD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_B057D503408B9FB6E6093AF3DA579046" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_D5406A3D9C1C7708D7AA3AF3DA576847" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_B057D503408B9FB6E6093AF3DA579046" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_A66311ADF0624C03001D3AF3DA57005C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_B057D503408B9FB6E6093AF3DA579046" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_A66311ADF0624C03001D3AF3DA57005C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_A66311ADF0624C03001D3AF3DA57005C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_B057D503408B9FB6E6093AF3DA579046" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_A66311ADF0624C03001D3AF3DA57005C" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ConvertiblePreferredStockWarrantLiabilityMember" xlink:label="loc_enph_ConvertiblePreferredStockWarrantLiabilityMember_4B3268CC59241A2624713AF3DA57BDFB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_A66311ADF0624C03001D3AF3DA57005C" xlink:to="loc_enph_ConvertiblePreferredStockWarrantLiabilityMember_4B3268CC59241A2624713AF3DA57BDFB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_EDD20F52505A5860F7D93AF3DA573594" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_D5406A3D9C1C7708D7AA3AF3DA576847" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_EDD20F52505A5860F7D93AF3DA573594" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_EDD20F52505A5860F7D93AF3DA573594" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_EDD20F52505A5860F7D93AF3DA573594" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_WarrantsToPurchasePreferredStockIssueOneMember" xlink:label="loc_enph_WarrantsToPurchasePreferredStockIssueOneMember_38836ED0E34B153A121F3AF3DA58C1E4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA" xlink:to="loc_enph_WarrantsToPurchasePreferredStockIssueOneMember_38836ED0E34B153A121F3AF3DA58C1E4" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_WarrantsToPurchasePreferredStockIssueTwoMember" xlink:label="loc_enph_WarrantsToPurchasePreferredStockIssueTwoMember_48B70BBCEF49C0EF3C643AF3DA581DA4" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_E1837E4E2EC0BCD17A8A3AF3DA58DFDA" xlink:to="loc_enph_WarrantsToPurchasePreferredStockIssueTwoMember_48B70BBCEF49C0EF3C643AF3DA581DA4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_5EB0DB1E5FACA5E1E02C3AF3DA58873D" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_1C39DA5180737B3DE4A13AF3DA583284" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_1C39DA5180737B3DE4A13AF3DA583284" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_3179BE9F2DC0FF9B001C3AF3DA584C47" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_3179BE9F2DC0FF9B001C3AF3DA584C47" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisGainLossIncludedInOtherIncome" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisGainLossIncludedInOtherIncome_11C7D42CD2580FEBEFEB3AF3DA580622" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisGainLossIncludedInOtherIncome_11C7D42CD2580FEBEFEB3AF3DA580622" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ReclassificationOfPreferredStockWarrantLiability" xlink:label="loc_enph_ReclassificationOfPreferredStockWarrantLiability_B6ECE47EFF3607A490543AF3DA589EDA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_4EE30A8A271F4DFF21293AF3DA5885BF" xlink:to="loc_enph_ReclassificationOfPreferredStockWarrantLiability_B6ECE47EFF3607A490543AF3DA589EDA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_B7FD20022150652F156F3AF3DA58F246" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_5EB0DB1E5FACA5E1E02C3AF3DA58873D" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_B7FD20022150652F156F3AF3DA58F246" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_1426800CE9CF2429A2EC3AF3DA587AEB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_5EB0DB1E5FACA5E1E02C3AF3DA58873D" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_1426800CE9CF2429A2EC3AF3DA587AEB" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/StockholdersEquityAndWarrantsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/StockholdersEquityAndWarrantsValuationAssumptionsOfConvertiblePreferredStockWarrantsUnderMonteCarloSimulationModelDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_68DBC24D5157A1C2DEFF35F458F4DEFC" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_515FB1A68B4B02775D7435F458EF1D84" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_68DBC24D5157A1C2DEFF35F458F4DEFC" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_515FB1A68B4B02775D7435F458EF1D84" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_DF52AF9D9A26BE83C48736161C230FF3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_515FB1A68B4B02775D7435F458EF1D84" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_DF52AF9D9A26BE83C48736161C230FF3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_16A8973ACFEF3BDC13B436161C289796_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_DF52AF9D9A26BE83C48736161C230FF3" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_16A8973ACFEF3BDC13B436161C289796_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_16A8973ACFEF3BDC13B436161C289796" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_DF52AF9D9A26BE83C48736161C230FF3" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_16A8973ACFEF3BDC13B436161C289796" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ConvertiblePreferredStockWarrantLiabilityMember" xlink:label="loc_enph_ConvertiblePreferredStockWarrantLiabilityMember_83934E39EC5330DE7C3C36171A4722E0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_16A8973ACFEF3BDC13B436161C289796" xlink:to="loc_enph_ConvertiblePreferredStockWarrantLiabilityMember_83934E39EC5330DE7C3C36171A4722E0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_F808705274A6BAA2E3D835F458EFD885" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_515FB1A68B4B02775D7435F458EF1D84" xlink:to="loc_us-gaap_StatementClassOfStockAxis_F808705274A6BAA2E3D835F458EFD885" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3D9BED23668EC272F80635F458EFCA31_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F808705274A6BAA2E3D835F458EFD885" xlink:to="loc_us-gaap_ClassOfStockDomain_3D9BED23668EC272F80635F458EFCA31_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3D9BED23668EC272F80635F458EFCA31" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F808705274A6BAA2E3D835F458EFD885" xlink:to="loc_us-gaap_ClassOfStockDomain_3D9BED23668EC272F80635F458EFCA31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_985FE5FEF8AF382E514435F458F4555D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3D9BED23668EC272F80635F458EFCA31" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_985FE5FEF8AF382E514435F458F4555D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_42F064B21BCB604EDF9535F458F42ADE" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_515FB1A68B4B02775D7435F458EF1D84" xlink:to="loc_us-gaap_RangeAxis_42F064B21BCB604EDF9535F458F42ADE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_42F064B21BCB604EDF9535F458F42ADE" xlink:to="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_42F064B21BCB604EDF9535F458F42ADE" xlink:to="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_85E1EF6689C9B4379EAB35F458F40A9E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA" xlink:to="loc_us-gaap_MinimumMember_85E1EF6689C9B4379EAB35F458F40A9E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_1F8BBF0DFD09B7269B0935F458F48B8D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_1E5661EA8772E322523B35F458F4DDBA" xlink:to="loc_us-gaap_MaximumMember_1F8BBF0DFD09B7269B0935F458F48B8D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract" xlink:label="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_68DBC24D5157A1C2DEFF35F458F4DEFC" xlink:to="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssumptionsExpectedTerm" xlink:label="loc_us-gaap_FairValueAssumptionsExpectedTerm_25A3209A424879982FAB35F458F51AC3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:to="loc_us-gaap_FairValueAssumptionsExpectedTerm_25A3209A424879982FAB35F458F51AC3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_FairValueAssumptionsExpectedVolatilityRate_D19F06F98152B49E44D935F458F57511" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:to="loc_us-gaap_FairValueAssumptionsExpectedVolatilityRate_D19F06F98152B49E44D935F458F57511" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_FairValueAssumptionsRiskFreeInterestRate_B23525514EF1956DE47735F458F5A961" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:to="loc_us-gaap_FairValueAssumptionsRiskFreeInterestRate_B23525514EF1956DE47735F458F5A961" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_FairValueAssumptionsExpectedDividendRate_5D6524B0EC00902A0FB635F458F571C6" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssumptionsAndMethodologyForAssetsAndLiabilitiesAbstract_4CBF66E3A2FD0F79ECB735F458F53DE7" xlink:to="loc_us-gaap_FairValueAssumptionsExpectedDividendRate_5D6524B0EC00902A0FB635F458F571C6" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/SummaryOfInventoryDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <loc xlink:href="enph-20121231.xsd#enph_AccountingPoliciesLineItems" xlink:label="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:type="locator" />
    <loc xlink:href="enph-20121231.xsd#enph_AccountingPoliciesTable" xlink:label="loc_enph_AccountingPoliciesTable_2623DD4AAAFACC8EED003C22AFE65D5C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_enph_AccountingPoliciesTable_2623DD4AAAFACC8EED003C22AFE65D5C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_F8698E88BA64D82149353C22AFE7050F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_enph_AccountingPoliciesTable_2623DD4AAAFACC8EED003C22AFE65D5C" xlink:to="loc_us-gaap_RangeAxis_F8698E88BA64D82149353C22AFE7050F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_F8698E88BA64D82149353C22AFE7050F" xlink:to="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_F8698E88BA64D82149353C22AFE7050F" xlink:to="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_2A88C89B0E9346397BA83C22AFEC7C08" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2" xlink:to="loc_us-gaap_MinimumMember_2A88C89B0E9346397BA83C22AFEC7C08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_78396AC9FFAD998710903C22AFECA5F3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_45092DE874CBD243321C3C22AFE712F2" xlink:to="loc_us-gaap_MaximumMember_78396AC9FFAD998710903C22AFECA5F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_559A2F2E6E1A720222A13C22AFEC9523" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_enph_AccountingPoliciesTable_2623DD4AAAFACC8EED003C22AFE65D5C" xlink:to="loc_us-gaap_ProductOrServiceAxis_559A2F2E6E1A720222A13C22AFEC9523" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ProductOrServiceAxis_559A2F2E6E1A720222A13C22AFEC9523" xlink:to="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ProductOrServiceAxis_559A2F2E6E1A720222A13C22AFEC9523" xlink:to="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_ACE31228AB5BE73096413C22AFED3F85" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174" xlink:to="loc_us-gaap_ProductMember_ACE31228AB5BE73096413C22AFED3F85" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_MicroinvertersMember" xlink:label="loc_enph_MicroinvertersMember_718D1DE6C3777CAEAF5F3C22AFED6049" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_ACE31228AB5BE73096413C22AFED3F85" xlink:to="loc_enph_MicroinvertersMember_718D1DE6C3777CAEAF5F3C22AFED6049" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_FirstAndSecondGenerationMember" xlink:label="loc_enph_FirstAndSecondGenerationMember_E3CBF34162EE3088E9CE3C22AFEDC7F0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_MicroinvertersMember_718D1DE6C3777CAEAF5F3C22AFED6049" xlink:to="loc_enph_FirstAndSecondGenerationMember_E3CBF34162EE3088E9CE3C22AFEDC7F0" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ThirdGenerationMember" xlink:label="loc_enph_ThirdGenerationMember_4A1B54D9A2264E65EF613C22AFED3F0F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_MicroinvertersMember_718D1DE6C3777CAEAF5F3C22AFED6049" xlink:to="loc_enph_ThirdGenerationMember_4A1B54D9A2264E65EF613C22AFED3F0F" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ServiceMember" xlink:label="loc_enph_ServiceMember_DCAD2EF2DF6C9CDE7D673C22AFED3644" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_A613360FA96C91EE77A03C22AFEDC174" xlink:to="loc_enph_ServiceMember_DCAD2EF2DF6C9CDE7D673C22AFED3644" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_EnlightenWebBasedMonitoringServiceMember" xlink:label="loc_enph_EnlightenWebBasedMonitoringServiceMember_9D269E6CC693D0E571503C22AFED1979" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_ServiceMember_DCAD2EF2DF6C9CDE7D673C22AFED3644" xlink:to="loc_enph_EnlightenWebBasedMonitoringServiceMember_9D269E6CC693D0E571503C22AFED1979" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RevenueNetPercentage" xlink:label="loc_enph_RevenueNetPercentage_AE773BA9F566F9CBF1343C22AFEE2B5C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_enph_RevenueNetPercentage_AE773BA9F566F9CBF1343C22AFEE2B5C" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_RevenueRecognitionRecognitionPeriod" xlink:label="loc_enph_RevenueRecognitionRecognitionPeriod_0C07488D3894FBA8E0C73C22AFEE184C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_enph_RevenueRecognitionRecognitionPeriod_0C07488D3894FBA8E0C73C22AFEE184C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenue" xlink:label="loc_us-gaap_DeferredRevenue_15DA281D50E413B7FA593C22AFEE907C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_DeferredRevenue_15DA281D50E413B7FA593C22AFEE907C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleDebtFairValueDisclosures" xlink:label="loc_us-gaap_ConvertibleDebtFairValueDisclosures_CDA8DE9C4003337EBDD43C22AFEE48D8" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_ConvertibleDebtFairValueDisclosures_CDA8DE9C4003337EBDD43C22AFEE48D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_4BF99D561030019025503C22AFEE2951" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_4BF99D561030019025503C22AFEE2951" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_F36723663C72BC33579E3C22AFEEA449" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_F36723663C72BC33579E3C22AFEEA449" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_ProductWarrantyCoveragePeriod" xlink:label="loc_enph_ProductWarrantyCoveragePeriod_F5667AD8E1E2975DD74D3C22AFEED8D2" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_enph_ProductWarrantyCoveragePeriod_F5667AD8E1E2975DD74D3C22AFEED8D2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductWarrantyExpense" xlink:label="loc_us-gaap_ProductWarrantyExpense_5F745467F70AB71BC5E83C22AFEEC429" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_ProductWarrantyExpense_5F745467F70AB71BC5E83C22AFEEC429" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_964E3ACC667C9761A5103C22AFEE41B4" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_964E3ACC667C9761A5103C22AFEE41B4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_ED01A75349424BD1FBCF3C22AFEEF341" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_ED01A75349424BD1FBCF3C22AFEEF341" xlink:type="arc" />
    <loc xlink:href="enph-20121231.xsd#enph_WarrantsFairValueAmountOutstanding" xlink:label="loc_enph_WarrantsFairValueAmountOutstanding_D04BBEB6281A80F60E773C22AFEE6B11" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_enph_WarrantsFairValueAmountOutstanding_D04BBEB6281A80F60E773C22AFEE6B11" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredOfferingCosts" xlink:label="loc_us-gaap_DeferredOfferingCosts_EBF0985B0D9FA22A51BB3C22AFEE9D4B" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AccountingPoliciesLineItems_7E5DDD69F0FF026BF68A3C22AFEE67D7" xlink:to="loc_us-gaap_DeferredOfferingCosts_EBF0985B0D9FA22A51BB3C22AFEE9D4B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.enphase.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/WarrantyObligationsNarrativeDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/WarrantyObligationsSummaryOfWarrantyObligationsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.enphase.com/role/WarrantyObligationsTables" xlink:type="extended" />
</linkbase>
