<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<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://enphase.com/role/CommitmentsAndContingencies" xlink:href="enph-20160331.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnaudited" xlink:href="enph-20160331.xsd#CondensedConsolidatedBalanceSheetsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:href="enph-20160331.xsd#CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:href="enph-20160331.xsd#CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:href="enph-20160331.xsd#CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:href="enph-20160331.xsd#CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:href="enph-20160331.xsd#DescriptionOfBusinessAndBasisOfPresentation" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:href="enph-20160331.xsd#DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:href="enph-20160331.xsd#DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/DocumentAndEntityInformation" xlink:href="enph-20160331.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurements" xlink:href="enph-20160331.xsd#FairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsNarrativeDetails" xlink:href="enph-20160331.xsd#FairValueMeasurementsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" xlink:href="enph-20160331.xsd#FairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsScheduleOfChangesInNonfinancialLiabilitiesRelatedToWarrantObligationsMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:href="enph-20160331.xsd#FairValueMeasurementsScheduleOfChangesInNonfinancialLiabilitiesRelatedToWarrantObligationsMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsSummaryOfChangesInFinancialLiabilitiesRelatedToContingentConsiderationMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:href="enph-20160331.xsd#FairValueMeasurementsSummaryOfChangesInFinancialLiabilitiesRelatedToContingentConsiderationMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsSummaryOfSignificantUnobservableInputsUsedInFairValueMeasurementOfLiabilitiesDesignatedAsLevel3Details" xlink:href="enph-20160331.xsd#FairValueMeasurementsSummaryOfSignificantUnobservableInputsUsedInFairValueMeasurementOfLiabilitiesDesignatedAsLevel3Details" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsTables" xlink:href="enph-20160331.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/GoodwillAndIntangibleAssets" xlink:href="enph-20160331.xsd#GoodwillAndIntangibleAssets" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/GoodwillAndIntangibleAssetsNarrativeDetails" xlink:href="enph-20160331.xsd#GoodwillAndIntangibleAssetsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/GoodwillAndIntangibleAssetsScheduleOfEstimatedFutureAmortizationExpenseRelatedToFiniteLivedIntangibleAssetsDetails" xlink:href="enph-20160331.xsd#GoodwillAndIntangibleAssetsScheduleOfEstimatedFutureAmortizationExpenseRelatedToFiniteLivedIntangibleAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:href="enph-20160331.xsd#GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/GoodwillAndIntangibleAssetsTables" xlink:href="enph-20160331.xsd#GoodwillAndIntangibleAssetsTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/IncomeTaxes" xlink:href="enph-20160331.xsd#IncomeTaxes" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/Inventory" xlink:href="enph-20160331.xsd#Inventory" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/InventorySummaryOfInventoryDetails" xlink:href="enph-20160331.xsd#InventorySummaryOfInventoryDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/InventoryTables" xlink:href="enph-20160331.xsd#InventoryTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShare" xlink:href="enph-20160331.xsd#NetLossPerShare" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareScheduleOfComputationOfBasicAndDilutedNetLossPerShareDetails" xlink:href="enph-20160331.xsd#NetLossPerShareScheduleOfComputationOfBasicAndDilutedNetLossPerShareDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareScheduleOfPotentiallyDilutiveSecuritiesExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:href="enph-20160331.xsd#NetLossPerShareScheduleOfPotentiallyDilutiveSecuritiesExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareTables" xlink:href="enph-20160331.xsd#NetLossPerShareTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/RevolvingCreditFacility" xlink:href="enph-20160331.xsd#RevolvingCreditFacility" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/RevolvingCreditFacilityNarrativeDetails" xlink:href="enph-20160331.xsd#RevolvingCreditFacilityNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensation" xlink:href="enph-20160331.xsd#StockBasedCompensation" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationNarrativeDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationSummaryOfComponentsOfTotalStockBasedCompensationExpenseDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationSummaryOfComponentsOfTotalStockBasedCompensationExpenseDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationSummaryOfRestrictedStockUnitActivityDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationSummaryOfRestrictedStockUnitActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationSummaryOfStockBasedCompensationAssociatedWithEachTypeOfAwardDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationSummaryOfStockBasedCompensationAssociatedWithEachTypeOfAwardDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationSummaryOfStockOptionActivityDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationSummaryOfStockOptionActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationSummaryOfWeightedAverageGrantDateFairValueOfOptionsGrantedDetails" xlink:href="enph-20160331.xsd#StockBasedCompensationSummaryOfWeightedAverageGrantDateFairValueOfOptionsGrantedDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationTables" xlink:href="enph-20160331.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligations" xlink:href="enph-20160331.xsd#WarrantyObligations" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligationsNarrativeDetails" xlink:href="enph-20160331.xsd#WarrantyObligationsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligationsSummaryOfWarrantyActivitiesDetails" xlink:href="enph-20160331.xsd#WarrantyObligationsSummaryOfWarrantyActivitiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligationsTables" xlink:href="enph-20160331.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://enphase.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnaudited" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductInformationLineItems" xlink:label="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfProductInformationTable" xlink:label="loc_us-gaap_ScheduleOfProductInformationTable_F5284C3C95A25E4CB8B672CAB6DE83BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:to="loc_us-gaap_ScheduleOfProductInformationTable_F5284C3C95A25E4CB8B672CAB6DE83BF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_FECE5C43E92A1019182572CAB6DE089C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable_F5284C3C95A25E4CB8B672CAB6DE83BF" xlink:to="loc_us-gaap_ProductOrServiceAxis_FECE5C43E92A1019182572CAB6DE089C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ProductOrServiceAxis_FECE5C43E92A1019182572CAB6DE089C" xlink:to="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ProductOrServiceAxis_FECE5C43E92A1019182572CAB6DE089C" xlink:to="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_MicroinverterMember" xlink:label="loc_enph_MicroinverterMember_AAD80E67A251B7A3A4DC72CAB7162F3C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2" xlink:to="loc_enph_MicroinverterMember_AAD80E67A251B7A3A4DC72CAB7162F3C" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_ResidentialAndCommercialSystemsMember" xlink:label="loc_enph_ResidentialAndCommercialSystemsMember_7D6B11BBF200E966677C72CAB7223517" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_545795EA69B4B81E0D8372CAB6DFB2E2" xlink:to="loc_enph_ResidentialAndCommercialSystemsMember_7D6B11BBF200E966677C72CAB7223517" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E0556509135CF54CDE4172CAB6DF07D9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable_F5284C3C95A25E4CB8B672CAB6DE83BF" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E0556509135CF54CDE4172CAB6DF07D9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_655C3FBD846C92DA582772CAB6E04751_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E0556509135CF54CDE4172CAB6DF07D9" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_655C3FBD846C92DA582772CAB6E04751_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_655C3FBD846C92DA582772CAB6E04751" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E0556509135CF54CDE4172CAB6DF07D9" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_655C3FBD846C92DA582772CAB6E04751" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NumberOfProductShipped" xlink:label="loc_enph_NumberOfProductShipped_701064AD4337F5EF1D4B72CC2597BAAD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:to="loc_enph_NumberOfProductShipped_701064AD4337F5EF1D4B72CC2597BAAD" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NumberOfWatts" xlink:label="loc_enph_NumberOfWatts_E8FA93FA35D2F2D30B2272CAB6F41961" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:to="loc_enph_NumberOfWatts_E8FA93FA35D2F2D30B2272CAB6F41961" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NumberOfProductDeployed" xlink:label="loc_enph_NumberOfProductDeployed_E3B59CB35801D5F317D472CAB700E19E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:to="loc_enph_NumberOfProductDeployed_E3B59CB35801D5F317D472CAB700E19E" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NumberOfCountriesInWhichProductIsDeployed" xlink:label="loc_enph_NumberOfCountriesInWhichProductIsDeployed_8418BC98408C7229674F72CAB70B7D6D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductInformationLineItems_05A75597C6DC4C8B9F1972CAB6E06C17" xlink:to="loc_enph_NumberOfCountriesInWhichProductIsDeployed_8418BC98408C7229674F72CAB70B7D6D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurements" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_8E771064E3F8361EB83430937A1F3ACB" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_8E771064E3F8361EB83430937A1F3ACB" xlink:to="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_359CA0316F2B16F23B2730937A1C846A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_HedgingDesignationAxis_359CA0316F2B16F23B2730937A1C846A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_76DF44EBD9F442EEAF0430937A1C0DC6_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_359CA0316F2B16F23B2730937A1C846A" xlink:to="loc_us-gaap_HedgingDesignationDomain_76DF44EBD9F442EEAF0430937A1C0DC6_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_76DF44EBD9F442EEAF0430937A1C0DC6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_359CA0316F2B16F23B2730937A1C846A" xlink:to="loc_us-gaap_HedgingDesignationDomain_76DF44EBD9F442EEAF0430937A1C0DC6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_D1C2B7EB7DAB762596A930937A1DCC5F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_76DF44EBD9F442EEAF0430937A1C0DC6" xlink:to="loc_us-gaap_NondesignatedMember_D1C2B7EB7DAB762596A930937A1DCC5F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_BEC70A5E85BB128C682830937A1DF7C5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_BEC70A5E85BB128C682830937A1DF7C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7C7D843FB3F16373F96F30937A1DC140_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_BEC70A5E85BB128C682830937A1DF7C5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7C7D843FB3F16373F96F30937A1DC140_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7C7D843FB3F16373F96F30937A1DC140" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_BEC70A5E85BB128C682830937A1DF7C5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7C7D843FB3F16373F96F30937A1DC140" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_4DD96C903DBE7728F0AD30937A1DF0C9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7C7D843FB3F16373F96F30937A1DC140" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_4DD96C903DBE7728F0AD30937A1DF0C9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_25FD536B42C7B342476D30937A1DB01B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_25FD536B42C7B342476D30937A1DB01B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BB7289E6A8F6EBA890C930937A1D3DF7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_25FD536B42C7B342476D30937A1DB01B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BB7289E6A8F6EBA890C930937A1D3DF7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BB7289E6A8F6EBA890C930937A1D3DF7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_25FD536B42C7B342476D30937A1DB01B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BB7289E6A8F6EBA890C930937A1D3DF7" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NextPhaseSolarInc.Member" xlink:label="loc_enph_NextPhaseSolarInc.Member_7AAA53B5274941ABFA2530937A1DF020" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BB7289E6A8F6EBA890C930937A1D3DF7" xlink:to="loc_enph_NextPhaseSolarInc.Member_7AAA53B5274941ABFA2530937A1DF020" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueAxis" xlink:label="loc_us-gaap_ValuationTechniqueAxis_5664EF20CDA01BA534BB30937A1EA6B2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_ValuationTechniqueAxis_5664EF20CDA01BA534BB30937A1EA6B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_D1C2859ABB591BD63CCB30937A1ECE00_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_5664EF20CDA01BA534BB30937A1EA6B2" xlink:to="loc_us-gaap_ValuationTechniqueDomain_D1C2859ABB591BD63CCB30937A1ECE00_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_D1C2859ABB591BD63CCB30937A1ECE00" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_5664EF20CDA01BA534BB30937A1EA6B2" xlink:to="loc_us-gaap_ValuationTechniqueDomain_D1C2859ABB591BD63CCB30937A1ECE00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeApproachValuationTechniqueMember" xlink:label="loc_us-gaap_IncomeApproachValuationTechniqueMember_877229AA76710A4B92EF30937A1E8955" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_D1C2859ABB591BD63CCB30937A1ECE00" xlink:to="loc_us-gaap_IncomeApproachValuationTechniqueMember_877229AA76710A4B92EF30937A1E8955" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_29F5A0F179807EF238DF30937A1E36CB" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_29F5A0F179807EF238DF30937A1E36CB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_9105DFF0E29D5E7A65F330937A1EDE0A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_29F5A0F179807EF238DF30937A1E36CB" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_9105DFF0E29D5E7A65F330937A1EDE0A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_9105DFF0E29D5E7A65F330937A1EDE0A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_29F5A0F179807EF238DF30937A1E36CB" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_9105DFF0E29D5E7A65F330937A1EDE0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_EA14EAE7FCBBD139ADC730937A1E8A09" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_9105DFF0E29D5E7A65F330937A1EDE0A" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_EA14EAE7FCBBD139ADC730937A1E8A09" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44A4819A94922D839D2530937A1EA702" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44A4819A94922D839D2530937A1EA702" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A943C32ECF70FFFDBC8530937A1EAD7D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44A4819A94922D839D2530937A1EA702" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A943C32ECF70FFFDBC8530937A1EAD7D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A943C32ECF70FFFDBC8530937A1EAD7D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44A4819A94922D839D2530937A1EA702" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A943C32ECF70FFFDBC8530937A1EAD7D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_CF82517C12D458D9FCF630937A1E2F88" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A943C32ECF70FFFDBC8530937A1EAD7D" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_CF82517C12D458D9FCF630937A1E2F88" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EligibleItemOrGroupForFairValueOptionAxis" xlink:label="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_10F381C65AD289FABA4A30937A1E92D0" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_A159C4BF6FBC570394F730937A1CCFA7" xlink:to="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_10F381C65AD289FABA4A30937A1E92D0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5E6FD287A23F689201E730937A1E9EF4_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_10F381C65AD289FABA4A30937A1E92D0" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5E6FD287A23F689201E730937A1E9EF4_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5E6FD287A23F689201E730937A1E9EF4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_10F381C65AD289FABA4A30937A1E92D0" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5E6FD287A23F689201E730937A1E9EF4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GuaranteesMember" xlink:label="loc_us-gaap_GuaranteesMember_807F3CE687F59E23F18330937A1E078B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5E6FD287A23F689201E730937A1E9EF4" xlink:to="loc_us-gaap_GuaranteesMember_807F3CE687F59E23F18330937A1E078B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_458CB3F1CA481BE7F0F530937A1FD1D8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8E771064E3F8361EB83430937A1F3ACB" xlink:to="loc_invest_DerivativeNotionalAmount_458CB3F1CA481BE7F0F530937A1FD1D8" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_WarrantyObligationsatFairValueDecreaseinFairValueResultingfromOnePercentagePointIncreaseinDiscountRate" xlink:label="loc_enph_WarrantyObligationsatFairValueDecreaseinFairValueResultingfromOnePercentagePointIncreaseinDiscountRate_18EB2B74B5EDDB2B905730937A1F4E36" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8E771064E3F8361EB83430937A1F3ACB" xlink:to="loc_enph_WarrantyObligationsatFairValueDecreaseinFairValueResultingfromOnePercentagePointIncreaseinDiscountRate_18EB2B74B5EDDB2B905730937A1F4E36" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate" xlink:label="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate_0060036B1E275588FFDD30937A1F5BD0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8E771064E3F8361EB83430937A1F3ACB" xlink:to="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate_0060036B1E275588FFDD30937A1F5BD0" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_821D7E9F3A5A52F0A85DC2D39F40F31B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1BBB4BA48D19565E9261147140642359" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_821D7E9F3A5A52F0A85DC2D39F40F31B" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1BBB4BA48D19565E9261147140642359" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F09445846950518B85F5AC92137BD3BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1BBB4BA48D19565E9261147140642359" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F09445846950518B85F5AC92137BD3BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_564FF2EB5B828DE101E467020140E17A_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F09445846950518B85F5AC92137BD3BF" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_564FF2EB5B828DE101E467020140E17A_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_2680962AEF6C52EDBF831E10B8AF11B5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F09445846950518B85F5AC92137BD3BF" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_2680962AEF6C52EDBF831E10B8AF11B5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_0BC43D54579D511893BB57BE7F556524" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_2680962AEF6C52EDBF831E10B8AF11B5" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_0BC43D54579D511893BB57BE7F556524" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E228B94EE7C058DBA92D0A878318D528" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1BBB4BA48D19565E9261147140642359" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E228B94EE7C058DBA92D0A878318D528" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_56BD8FEB18E5DC5C695367020141D47B_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E228B94EE7C058DBA92D0A878318D528" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_56BD8FEB18E5DC5C695367020141D47B_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_DE16663205755FFA9F7D04DAEA25979C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E228B94EE7C058DBA92D0A878318D528" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_DE16663205755FFA9F7D04DAEA25979C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_8F7B48F4597C5F12B39B20BB33590FB3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_DE16663205755FFA9F7D04DAEA25979C" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_8F7B48F4597C5F12B39B20BB33590FB3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_3A98B44CEB615FCFB45E862EA92B18B4" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_DE16663205755FFA9F7D04DAEA25979C" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_3A98B44CEB615FCFB45E862EA92B18B4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_B669F1E133A15179A8AA637C64D0738F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1BBB4BA48D19565E9261147140642359" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_B669F1E133A15179A8AA637C64D0738F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_9CD18D8EC9653569851267020141BFA7_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_B669F1E133A15179A8AA637C64D0738F" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_9CD18D8EC9653569851267020141BFA7_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_94C59A53985456EC8F2CDFFEA41ED5B3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_B669F1E133A15179A8AA637C64D0738F" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_94C59A53985456EC8F2CDFFEA41ED5B3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_8210BDE006FD584EB7A75DC90E6FF78F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_94C59A53985456EC8F2CDFFEA41ED5B3" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_8210BDE006FD584EB7A75DC90E6FF78F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GuaranteesMember" xlink:label="loc_us-gaap_GuaranteesMember_554187F2BBFD59A9984E79CFDB18A021" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_94C59A53985456EC8F2CDFFEA41ED5B3" xlink:to="loc_us-gaap_GuaranteesMember_554187F2BBFD59A9984E79CFDB18A021" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_5C61495B3B6F5C2D96F4C144CB671226" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_821D7E9F3A5A52F0A85DC2D39F40F31B" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_5C61495B3B6F5C2D96F4C144CB671226" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ForeignCurrencyContractAssetFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_D291B87E94C551CBBF8BD47246C1F80B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_5C61495B3B6F5C2D96F4C144CB671226" xlink:to="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_D291B87E94C551CBBF8BD47246C1F80B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_21572E0725B153FE9AF7B03BC6A68727" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_821D7E9F3A5A52F0A85DC2D39F40F31B" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_21572E0725B153FE9AF7B03BC6A68727" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_90CD987F616C560F9313D841A2202F2A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_21572E0725B153FE9AF7B03BC6A68727" xlink:to="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_90CD987F616C560F9313D841A2202F2A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_723825545BA55D478A30185E19D955DA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_21572E0725B153FE9AF7B03BC6A68727" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_723825545BA55D478A30185E19D955DA" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsScheduleOfChangesInNonfinancialLiabilitiesRelatedToWarrantObligationsMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_F816B9792E2A51FDA63FCD9CAD3D0613" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_F66399F0D0FC53D0B04AF1A666FA30F4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_F816B9792E2A51FDA63FCD9CAD3D0613" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_F66399F0D0FC53D0B04AF1A666FA30F4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_C2DD844138E3565DA9DE3AC0C170A3CE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_F66399F0D0FC53D0B04AF1A666FA30F4" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_C2DD844138E3565DA9DE3AC0C170A3CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_C97B7D6045067DE6DD1BA5E5CA00221D_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_C2DD844138E3565DA9DE3AC0C170A3CE" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_C97B7D6045067DE6DD1BA5E5CA00221D_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_27ED592970E259BD933363CD0CF0C9A2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_C2DD844138E3565DA9DE3AC0C170A3CE" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_27ED592970E259BD933363CD0CF0C9A2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_18CDFE84C4E6551AAFF93E4B6AA7BDCA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_27ED592970E259BD933363CD0CF0C9A2" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_18CDFE84C4E6551AAFF93E4B6AA7BDCA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_B5932FA900785FC1BD4CF72BF6FAA27D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_F66399F0D0FC53D0B04AF1A666FA30F4" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_B5932FA900785FC1BD4CF72BF6FAA27D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_B443BA13313EA8A0F04EA5E5CA00177D_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_B5932FA900785FC1BD4CF72BF6FAA27D" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_B443BA13313EA8A0F04EA5E5CA00177D_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_8751A3B8717B5044B9A396759784199E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_B5932FA900785FC1BD4CF72BF6FAA27D" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_8751A3B8717B5044B9A396759784199E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_9AB1C6FC232D519E928864E83AC28E5E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_8751A3B8717B5044B9A396759784199E" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_9AB1C6FC232D519E928864E83AC28E5E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_42F5A737B48E57FBA59356DBA22E2A9F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_F66399F0D0FC53D0B04AF1A666FA30F4" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_42F5A737B48E57FBA59356DBA22E2A9F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_31C0950E49036844D7C6A5E5CA00C50C_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_42F5A737B48E57FBA59356DBA22E2A9F" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_31C0950E49036844D7C6A5E5CA00C50C_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_84374FC17B585AB58057426595528622" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_42F5A737B48E57FBA59356DBA22E2A9F" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_84374FC17B585AB58057426595528622" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_290905AA95815EDFBB01B505FCB22584" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_84374FC17B585AB58057426595528622" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_290905AA95815EDFBB01B505FCB22584" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_F816B9792E2A51FDA63FCD9CAD3D0613" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_EDF71E055EE15592B636F9AE1C1806BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_EDF71E055EE15592B636F9AE1C1806BF" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued" xlink:label="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued_8C550B9B0BE65E0CA1970A5F0226F193" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued_8C550B9B0BE65E0CA1970A5F0226F193" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_FairValueMeasurementwithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeinEstimate" xlink:label="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeinEstimate_72159D9A6E225D72B788905F10AB2FAF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeinEstimate_72159D9A6E225D72B788905F10AB2FAF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_FE2B7AC1FB4453B18CA6E88BC38E53FA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_FE2B7AC1FB4453B18CA6E88BC38E53FA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_92ADE56A2359528BADA1909039BC5B70" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_92ADE56A2359528BADA1909039BC5B70" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisOther" xlink:label="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisOther_4FF62760BFC2591D99B3EA881E88E357" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E6FD86129FEB5833829BA84FC04CD798" xlink:to="loc_enph_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisOther_4FF62760BFC2591D99B3EA881E88E357" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsSummaryOfChangesInFinancialLiabilitiesRelatedToContingentConsiderationMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLiabilitiesQuantitativeInformationLineItems" xlink:label="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationLineItems_9AAD14B1040F57FAA94D442BEAD164FC" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable" xlink:label="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationLineItems_9AAD14B1040F57FAA94D442BEAD164FC" xlink:to="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_B1F1253E78A957A9A1C61406F4A210F2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_B1F1253E78A957A9A1C61406F4A210F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C5D4E4A1F309A4AF9FCC67020120D129_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_B1F1253E78A957A9A1C61406F4A210F2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C5D4E4A1F309A4AF9FCC67020120D129_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BDDE655EA77659F9BEE0E38A0AF7FFE8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_B1F1253E78A957A9A1C61406F4A210F2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BDDE655EA77659F9BEE0E38A0AF7FFE8" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_NextPhaseSolarInc.Member" xlink:label="loc_enph_NextPhaseSolarInc.Member_625B1A07ACCC56EBA29BF42A06970B65" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BDDE655EA77659F9BEE0E38A0AF7FFE8" xlink:to="loc_enph_NextPhaseSolarInc.Member_625B1A07ACCC56EBA29BF42A06970B65" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EligibleItemOrGroupForFairValueOptionAxis" xlink:label="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_209A7B8A25C3522D8A4C5F5906D64698" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:to="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_209A7B8A25C3522D8A4C5F5906D64698" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_D459B81EBAA0300E6BA7670201202493_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_209A7B8A25C3522D8A4C5F5906D64698" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_D459B81EBAA0300E6BA7670201202493_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5132144FD47D53D296436B0B0098A1E6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_209A7B8A25C3522D8A4C5F5906D64698" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5132144FD47D53D296436B0B0098A1E6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GuaranteesMember" xlink:label="loc_us-gaap_GuaranteesMember_7ADB929DCC6756608945280E1CFB7700" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_5132144FD47D53D296436B0B0098A1E6" xlink:to="loc_us-gaap_GuaranteesMember_7ADB929DCC6756608945280E1CFB7700" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_396412F70FB8568C937D38D894008E1E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_396412F70FB8568C937D38D894008E1E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_FBD6FE3C4D42D662A7C46702012084CD_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_396412F70FB8568C937D38D894008E1E" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_FBD6FE3C4D42D662A7C46702012084CD_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_E9F17FBC75AE5380915DFBADC60F3652" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_396412F70FB8568C937D38D894008E1E" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_E9F17FBC75AE5380915DFBADC60F3652" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_DE763B77FEFE5A64BAA0C7D1BC3E001C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_E9F17FBC75AE5380915DFBADC60F3652" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_DE763B77FEFE5A64BAA0C7D1BC3E001C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D4C906F0E04459E6A9EE433248C56C60" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationTable_1B9EC1B7695E50AB84262E56359A1DF9" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D4C906F0E04459E6A9EE433248C56C60" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_07E1627A85FDCB363817670201201E0A_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D4C906F0E04459E6A9EE433248C56C60" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_07E1627A85FDCB363817670201201E0A_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9A9E84E417EC58F4A7B241D18C1917F8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D4C906F0E04459E6A9EE433248C56C60" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9A9E84E417EC58F4A7B241D18C1917F8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_A2357C14AB6D51ABB565406A6C2670E2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9A9E84E417EC58F4A7B241D18C1917F8" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_A2357C14AB6D51ABB565406A6C2670E2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_0F057D951B51566498FF65DD1408CE34" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInputsLiabilitiesQuantitativeInformationLineItems_9AAD14B1040F57FAA94D442BEAD164FC" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_0F057D951B51566498FF65DD1408CE34" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_BDD6A67DCBC3545B904E4CADB2BC8117" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_0F057D951B51566498FF65DD1408CE34" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_BDD6A67DCBC3545B904E4CADB2BC8117" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityAdjustments" xlink:label="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityAdjustments_D6DF1422637A5F979F95C05BED3A0410" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_0F057D951B51566498FF65DD1408CE34" xlink:to="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityAdjustments_D6DF1422637A5F979F95C05BED3A0410" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsSummaryOfSignificantUnobservableInputsUsedInFairValueMeasurementOfLiabilitiesDesignatedAsLevel3Details" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_642F5CE6D4535303B50537F0F9001606" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_642F5CE6D4535303B50537F0F9001606" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueAxis" xlink:label="loc_us-gaap_ValuationTechniqueAxis_20431F6490F252F08BA1616DF72A02DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:to="loc_us-gaap_ValuationTechniqueAxis_20431F6490F252F08BA1616DF72A02DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_ACB78B3F20E17500FE8B670201543FFF_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_20431F6490F252F08BA1616DF72A02DC" xlink:to="loc_us-gaap_ValuationTechniqueDomain_ACB78B3F20E17500FE8B670201543FFF_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_762178E80A5F5B8C9C41A788D625B352" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_20431F6490F252F08BA1616DF72A02DC" xlink:to="loc_us-gaap_ValuationTechniqueDomain_762178E80A5F5B8C9C41A788D625B352" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeApproachValuationTechniqueMember" xlink:label="loc_us-gaap_IncomeApproachValuationTechniqueMember_7413EE31138352DCB4BDD179F9CD06FF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_762178E80A5F5B8C9C41A788D625B352" xlink:to="loc_us-gaap_IncomeApproachValuationTechniqueMember_7413EE31138352DCB4BDD179F9CD06FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_FD3FBFFE1FDF5132B5FB3EEB0199BF8D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_FD3FBFFE1FDF5132B5FB3EEB0199BF8D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_D574BF5F2B4A76631B7F67020155DED8_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_FD3FBFFE1FDF5132B5FB3EEB0199BF8D" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_D574BF5F2B4A76631B7F67020155DED8_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_CC3DD975F0AD5354A71B8C9F6AA3E068" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_FD3FBFFE1FDF5132B5FB3EEB0199BF8D" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_CC3DD975F0AD5354A71B8C9F6AA3E068" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_B48EE5934A045438BAE0A30C987D1DA8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_CC3DD975F0AD5354A71B8C9F6AA3E068" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_B48EE5934A045438BAE0A30C987D1DA8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4DEF67B933945C6A9EB93E7E73AA02AB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4DEF67B933945C6A9EB93E7E73AA02AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24011DD603C21FF5830667020155A0E4_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4DEF67B933945C6A9EB93E7E73AA02AB" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24011DD603C21FF5830667020155A0E4_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2CEFE239F7D5F2481E1DE26E23BA0E8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4DEF67B933945C6A9EB93E7E73AA02AB" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2CEFE239F7D5F2481E1DE26E23BA0E8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_C0C145519EF05AB495258331324FE99E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2CEFE239F7D5F2481E1DE26E23BA0E8" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_C0C145519EF05AB495258331324FE99E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EligibleItemOrGroupForFairValueOptionAxis" xlink:label="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_87883B9B2A355704A4C2B046F3A306DA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_B6DDBF920C7B5B7C80D78A5AB035A963" xlink:to="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_87883B9B2A355704A4C2B046F3A306DA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_9A964AA4C18484F5325867020155D3FC_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_87883B9B2A355704A4C2B046F3A306DA" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_9A964AA4C18484F5325867020155D3FC_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueOptionEligibleItemOrGroupDomain" xlink:label="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_2DA685C965FB58A0B3C4DC97ECE1D060" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EligibleItemOrGroupForFairValueOptionAxis_87883B9B2A355704A4C2B046F3A306DA" xlink:to="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_2DA685C965FB58A0B3C4DC97ECE1D060" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_2ABD8E9D277B58789BBD0322028EDA13" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_2DA685C965FB58A0B3C4DC97ECE1D060" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_2ABD8E9D277B58789BBD0322028EDA13" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GuaranteesMember" xlink:label="loc_us-gaap_GuaranteesMember_AF9921AE46FC5E2D83F2FC4498A81DE0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionEligibleItemOrGroupDomain_2DA685C965FB58A0B3C4DC97ECE1D060" xlink:to="loc_us-gaap_GuaranteesMember_AF9921AE46FC5E2D83F2FC4498A81DE0" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_FairValueInputsProfitElementandRiskPremium" xlink:label="loc_enph_FairValueInputsProfitElementandRiskPremium_196EEC2906D35BBBA01F6745D1B71F09" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_642F5CE6D4535303B50537F0F9001606" xlink:to="loc_enph_FairValueInputsProfitElementandRiskPremium_196EEC2906D35BBBA01F6745D1B71F09" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsEntityCreditRisk" xlink:label="loc_us-gaap_FairValueInputsEntityCreditRisk_A98553B12D1F50309061D757D7B3F951" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_642F5CE6D4535303B50537F0F9001606" xlink:to="loc_us-gaap_FairValueInputsEntityCreditRisk_A98553B12D1F50309061D757D7B3F951" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsDiscountRate" xlink:label="loc_us-gaap_FairValueInputsDiscountRate_88C1EEF1BBE35282A4D0986ED87E0340" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_642F5CE6D4535303B50537F0F9001606" xlink:to="loc_us-gaap_FairValueInputsDiscountRate_88C1EEF1BBE35282A4D0986ED87E0340" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/GoodwillAndIntangibleAssets" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/GoodwillAndIntangibleAssetsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_85F517A1E74F90CDF3DA5D9A248167E1" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_48CFF5419EA53038938D5D9A24816958" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_85F517A1E74F90CDF3DA5D9A248167E1" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_48CFF5419EA53038938D5D9A24816958" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96F2FC7E88BED51CECB35D9A2481BEB4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_48CFF5419EA53038938D5D9A24816958" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96F2FC7E88BED51CECB35D9A2481BEB4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96F2FC7E88BED51CECB35D9A2481BEB4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96F2FC7E88BED51CECB35D9A2481BEB4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_EAA770E0BBB97F63F3515D9A24817BBF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9" xlink:to="loc_us-gaap_CustomerRelationshipsMember_EAA770E0BBB97F63F3515D9A24817BBF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaap_PatentsMember_7EAAF588E5B3703D7C3A5D9A24819CC5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9" xlink:to="loc_us-gaap_PatentsMember_7EAAF588E5B3703D7C3A5D9A24819CC5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_C1B9F2B5443C816E660E5DC95437ECC7" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_18DEE2929AF9908CDB545D9A2481C9F9" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_C1B9F2B5443C816E660E5DC95437ECC7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_F265648E15AB139BA1FE5D9A2481D573" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_85F517A1E74F90CDF3DA5D9A248167E1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_F265648E15AB139BA1FE5D9A2481D573" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_39819943A63EC3DB72615D9A2481E511" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_85F517A1E74F90CDF3DA5D9A248167E1" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_39819943A63EC3DB72615D9A2481E511" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/GoodwillAndIntangibleAssetsScheduleOfEstimatedFutureAmortizationExpenseRelatedToFiniteLivedIntangibleAssetsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_27C24B5FD49F0D7149107776E7E14DF8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_27C24B5FD49F0D7149107776E7E14DF8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3E3FFC43EE153291F3C87776E7E10C2D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_27C24B5FD49F0D7149107776E7E14DF8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3E3FFC43EE153291F3C87776E7E10C2D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3E3FFC43EE153291F3C87776E7E10C2D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3E3FFC43EE153291F3C87776E7E10C2D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_465339665534E502CABC7776E7E15533" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE" xlink:to="loc_us-gaap_CustomerRelationshipsMember_465339665534E502CABC7776E7E15533" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaap_PatentsMember_A04D9C53245AC3CE84417776E7E36867" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D1BDD37C3EB864D565F37776E7E18FEE" xlink:to="loc_us-gaap_PatentsMember_A04D9C53245AC3CE84417776E7E36867" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_C25E3BA5F17209BF7E777776E7E438BD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:to="loc_us-gaap_GoodwillGross_C25E3BA5F17209BF7E777776E7E438BD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_2DB24243DD53D12AC6187776E7E408AC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:to="loc_us-gaap_Goodwill_2DB24243DD53D12AC6187776E7E408AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_78AFA55E4426C8913C937776E7E42638" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_78AFA55E4426C8913C937776E7E42638" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_6274832D27E81B18CCCF7776E7E4A0DA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D4793593D480B4BD58997776E7E303D2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_6274832D27E81B18CCCF7776E7E4A0DA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_347B6DB53FF7352FF8367776E7E455CD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_6274832D27E81B18CCCF7776E7E4A0DA" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_347B6DB53FF7352FF8367776E7E455CD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_068B4E7B19DF605E78077776E7E4FBF0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_6274832D27E81B18CCCF7776E7E4A0DA" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_068B4E7B19DF605E78077776E7E4FBF0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_77FE977E0A3A68ED5C4F7776E7E5BED2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_6274832D27E81B18CCCF7776E7E4A0DA" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_77FE977E0A3A68ED5C4F7776E7E5BED2" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/GoodwillAndIntangibleAssetsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/IncomeTaxes" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/Inventory" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/InventorySummaryOfInventoryDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/InventoryTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShare" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareScheduleOfComputationOfBasicAndDilutedNetLossPerShareDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareScheduleOfPotentiallyDilutiveSecuritiesExcludedFromComputationOfDilutedNetLossPerShareDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_E3690BEC3596ED2490FB309378F8ED7C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_DBC437B4BDE8C0E14A47309378F39886" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_E3690BEC3596ED2490FB309378F8ED7C" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_DBC437B4BDE8C0E14A47309378F39886" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9D2EA3F67875E37CD017309378F3E542" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_DBC437B4BDE8C0E14A47309378F39886" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9D2EA3F67875E37CD017309378F3E542" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9D2EA3F67875E37CD017309378F3E542" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9D2EA3F67875E37CD017309378F3E542" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_5FAB484FAA442B7CDF89309378F3652D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0" xlink:to="loc_us-gaap_EmployeeStockOptionMember_5FAB484FAA442B7CDF89309378F3652D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_6316E99A345F6109AB9F309378F36373" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_6316E99A345F6109AB9F309378F36373" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaap_WarrantMember_8E298C94B59791AB2C32309378F85894" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_5D2C6C70EBA04BD0F478309378F35AD0" xlink:to="loc_us-gaap_WarrantMember_8E298C94B59791AB2C32309378F85894" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_AntidilutiveSecuritiesAbstract" xlink:label="loc_enph_AntidilutiveSecuritiesAbstract_282A587D2F04D33F5CA7309378F9274A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_E3690BEC3596ED2490FB309378F8ED7C" xlink:to="loc_enph_AntidilutiveSecuritiesAbstract_282A587D2F04D33F5CA7309378F9274A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_71DC84BD25E14B020D89309378F92169" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AntidilutiveSecuritiesAbstract_282A587D2F04D33F5CA7309378F9274A" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_71DC84BD25E14B020D89309378F92169" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/RevolvingCreditFacility" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/RevolvingCreditFacilityNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_EA4E94B61522AFFE493F30ABE0B7FAD1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_EA4E94B61522AFFE493F30ABE0B7FAD1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0BD49A63F31A78EE47A430ABE0BF4650_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_EA4E94B61522AFFE493F30ABE0B7FAD1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0BD49A63F31A78EE47A430ABE0BF4650_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0BD49A63F31A78EE47A430ABE0BF4650" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_EA4E94B61522AFFE493F30ABE0B7FAD1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0BD49A63F31A78EE47A430ABE0BF4650" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_8C6EE77E7980588453E430ABE5E14414" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_0BD49A63F31A78EE47A430ABE0BF4650" xlink:to="loc_us-gaap_LineOfCreditMember_8C6EE77E7980588453E430ABE5E14414" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_E736428A0527D779E6A83093799B59EC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_E736428A0527D779E6A83093799B59EC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_5619B9E5C7DB56CD802E3093799B64E5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_E736428A0527D779E6A83093799B59EC" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_5619B9E5C7DB56CD802E3093799B64E5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_5619B9E5C7DB56CD802E3093799B64E5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_E736428A0527D779E6A83093799B59EC" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_5619B9E5C7DB56CD802E3093799B64E5" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_WellsFargoBankMember" xlink:label="loc_enph_WellsFargoBankMember_02D1FC854E9AE937A60A309379A08DF6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_5619B9E5C7DB56CD802E3093799B64E5" xlink:to="loc_enph_WellsFargoBankMember_02D1FC854E9AE937A60A309379A08DF6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_3EDBB434C65DAAEFA119309379A07363" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:to="loc_us-gaap_CreditFacilityAxis_3EDBB434C65DAAEFA119309379A07363" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_072131FC7ADAAB91CE13309379A09D7A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_3EDBB434C65DAAEFA119309379A07363" xlink:to="loc_us-gaap_CreditFacilityDomain_072131FC7ADAAB91CE13309379A09D7A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_072131FC7ADAAB91CE13309379A09D7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_3EDBB434C65DAAEFA119309379A07363" xlink:to="loc_us-gaap_CreditFacilityDomain_072131FC7ADAAB91CE13309379A09D7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_25F2E1EFBD7C9A6D39B9309379A0B768" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_072131FC7ADAAB91CE13309379A09D7A" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_25F2E1EFBD7C9A6D39B9309379A0B768" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_63FD7E0A7B26453FDB8C309379A0E16E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:to="loc_us-gaap_VariableRateAxis_63FD7E0A7B26453FDB8C309379A0E16E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_4A68C42403F6FC011151309379A08E7A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_63FD7E0A7B26453FDB8C309379A0E16E" xlink:to="loc_us-gaap_VariableRateDomain_4A68C42403F6FC011151309379A08E7A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_4A68C42403F6FC011151309379A08E7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_63FD7E0A7B26453FDB8C309379A0E16E" xlink:to="loc_us-gaap_VariableRateDomain_4A68C42403F6FC011151309379A08E7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_35461584A6A166A95EF0309379A1534B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_4A68C42403F6FC011151309379A08E7A" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_35461584A6A166A95EF0309379A1534B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_0BA868DF26FA06FF7304309379A10C79" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2F811A3DC1732D4AF6D23093799A0B1B" xlink:to="loc_us-gaap_RangeAxis_0BA868DF26FA06FF7304309379A10C79" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_0BA868DF26FA06FF7304309379A10C79" xlink:to="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_0BA868DF26FA06FF7304309379A10C79" xlink:to="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_DFB27B401A74F2C0A01B309379A1DEB4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440" xlink:to="loc_us-gaap_MinimumMember_DFB27B401A74F2C0A01B309379A1DEB4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_9C03297F3F5303FF060F309379A1AA08" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_B2FAF9F6CE597B1A16A7309379A16440" xlink:to="loc_us-gaap_MaximumMember_9C03297F3F5303FF060F309379A1AA08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_BB572EC715827592261B309379A11FFA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_BB572EC715827592261B309379A11FFA" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_LineOfCreditFacilityAccordionFeature" xlink:label="loc_enph_LineOfCreditFacilityAccordionFeature_F5D4DD69DD8753495FDD30ABDDF14F89" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_enph_LineOfCreditFacilityAccordionFeature_F5D4DD69DD8753495FDD30ABDDF14F89" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_95812E45B93BBB3458D2309379A1B234" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_95812E45B93BBB3458D2309379A1B234" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_A93E026981793CEDB59630ABDE8294A5" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_A93E026981793CEDB59630ABDE8294A5" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_AmountOfLiquidityRequiredForDebtCompliance" xlink:label="loc_enph_AmountOfLiquidityRequiredForDebtCompliance_B158554D627E46E4ACD2309379A104E8" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_enph_AmountOfLiquidityRequiredForDebtCompliance_B158554D627E46E4ACD2309379A104E8" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_AmountOfUndrawnCreditForDebtCompliance" xlink:label="loc_enph_AmountOfUndrawnCreditForDebtCompliance_0686AC45A102037CCA95309379A1A540" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_enph_AmountOfUndrawnCreditForDebtCompliance_0686AC45A102037CCA95309379A1A540" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LinesOfCreditCurrent" xlink:label="loc_us-gaap_LinesOfCreditCurrent_0B4136E3BF90DD9CFCB4309379A1C595" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_LinesOfCreditCurrent_0B4136E3BF90DD9CFCB4309379A1C595" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_C3F2E3CEAEFBB6F7526B309379A1134E" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_C3F2E3CEAEFBB6F7526B309379A1134E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtWeightedAverageInterestRate" xlink:label="loc_us-gaap_DebtWeightedAverageInterestRate_DD7A6E4601497374AC3E30ABDFAE6129" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_357DFA6ADF95C42F3D0B309379A1362D" xlink:to="loc_us-gaap_DebtWeightedAverageInterestRate_DD7A6E4601497374AC3E30ABDFAE6129" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensation" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_542AFE0C5AEA59D998C65CABEDDC0FB0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_542AFE0C5AEA59D998C65CABEDDC0FB0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_169965E9F6A75D718F8D9A63DA0F8B63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_542AFE0C5AEA59D998C65CABEDDC0FB0" xlink:to="loc_us-gaap_AwardTypeAxis_169965E9F6A75D718F8D9A63DA0F8B63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_094C07B15DF5DCD1E8C16702019EE29B_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_169965E9F6A75D718F8D9A63DA0F8B63" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_094C07B15DF5DCD1E8C16702019EE29B_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5AB03D3B8B21526BBD450BEEAB42CEDC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_169965E9F6A75D718F8D9A63DA0F8B63" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5AB03D3B8B21526BBD450BEEAB42CEDC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_1B158017F40E57C88A6BFBA168E1AB5B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5AB03D3B8B21526BBD450BEEAB42CEDC" xlink:to="loc_us-gaap_RestrictedStockMember_1B158017F40E57C88A6BFBA168E1AB5B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_E08CF6A7F20251F9BB6C25056E54FB63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_E08CF6A7F20251F9BB6C25056E54FB63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_DF92B4D52F735621928D9845256CB908" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_DF92B4D52F735621928D9845256CB908" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_C41AA79329045E80BC529E5C94DF7ABF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_C41AA79329045E80BC529E5C94DF7ABF" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsNonvestedIntrinsicValueValue" xlink:label="loc_enph_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsNonvestedIntrinsicValueValue_80AA1AA530BE52FC9CDB91542847F4F6" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_enph_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsNonvestedIntrinsicValueValue_80AA1AA530BE52FC9CDB91542847F4F6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_E909991E70F85FADB7E7745E21B4E50C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_E909991E70F85FADB7E7745E21B4E50C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_7369029921A850A4B9E06964E35A23B4" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C1FA0DEBF21C5A7CAADBE736339AC00A" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_7369029921A850A4B9E06964E35A23B4" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationSummaryOfComponentsOfTotalStockBasedCompensationExpenseDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_AF1AB9A27C915CE183A0271B2775EF2C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_0799B9E3E15E5CE1BC2B1B4438275813" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_AF1AB9A27C915CE183A0271B2775EF2C" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_0799B9E3E15E5CE1BC2B1B4438275813" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_2F960CB4E6205B688971AE0341B68434" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_0799B9E3E15E5CE1BC2B1B4438275813" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_2F960CB4E6205B688971AE0341B68434" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_140760B4B1B11D395719670201251F36_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2F960CB4E6205B688971AE0341B68434" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_140760B4B1B11D395719670201251F36_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2F960CB4E6205B688971AE0341B68434" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_FE67C2D44851542F96F662C5E292E238" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:to="loc_us-gaap_CostOfSalesMember_FE67C2D44851542F96F662C5E292E238" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_5E058332253653B494CA249F0536AADA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_5E058332253653B494CA249F0536AADA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_7A59549A31325B959893C1F1589321EB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_7A59549A31325B959893C1F1589321EB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_29FFD618D395518FAA5C8A3DE1CD3F1E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_A7831CDF18485816BEF213270D2692F2" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_29FFD618D395518FAA5C8A3DE1CD3F1E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_E3A00C78A93656A9A971C308346DAE51" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_AF1AB9A27C915CE183A0271B2775EF2C" xlink:to="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_E3A00C78A93656A9A971C308346DAE51" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_96E88B91F3B65133B3B62367BD7828DE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_E3A00C78A93656A9A971C308346DAE51" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_96E88B91F3B65133B3B62367BD7828DE" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationSummaryOfRestrictedStockUnitActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9DA2687791815E779496C6CFBCB4AE14" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C159BE2989F15A1FB4B46961B0DA276C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9DA2687791815E779496C6CFBCB4AE14" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C159BE2989F15A1FB4B46961B0DA276C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_6B102C77DEA45D79A351236D42C6C60D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C159BE2989F15A1FB4B46961B0DA276C" xlink:to="loc_us-gaap_AwardTypeAxis_6B102C77DEA45D79A351236D42C6C60D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_DB70ACC05CA091F6B1376702017BD317_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_6B102C77DEA45D79A351236D42C6C60D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_DB70ACC05CA091F6B1376702017BD317_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D56B7F22488A5693BBF23C5E20E2A7B7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_6B102C77DEA45D79A351236D42C6C60D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D56B7F22488A5693BBF23C5E20E2A7B7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_F8B0E1A47C165D71BA795199BA20CD76" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D56B7F22488A5693BBF23C5E20E2A7B7" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_F8B0E1A47C165D71BA795199BA20CD76" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9DA2687791815E779496C6CFBCB4AE14" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5D25796260AF5D11B2FE60A05397D196" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5D25796260AF5D11B2FE60A05397D196" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_BCFF3E7881F75FE49747CEF0969AA6E5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_BCFF3E7881F75FE49747CEF0969AA6E5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_35044918FDB45957AEADE5D201193F5A" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_35044918FDB45957AEADE5D201193F5A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_27047C61C2D95827BD8377BB2E0B572D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7A4D9DEACA6C54C1A5C8FE2D9554F840" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_27047C61C2D95827BD8377BB2E0B572D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9DA2687791815E779496C6CFBCB4AE14" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_9A3AF2FBA90D58FFAEC3F4F8A11671EF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_9A3AF2FBA90D58FFAEC3F4F8A11671EF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_EBDB66AB39C05884AA34CB2D68661BE1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_EBDB66AB39C05884AA34CB2D68661BE1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_3FBA28D0D229504DBCADFB102A805FFD" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_3FBA28D0D229504DBCADFB102A805FFD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_1FA90E7F51755E0B8A512A9948964A22" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_3C2A1BC6F93C5C4E9DB748672EF17F0A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_1FA90E7F51755E0B8A512A9948964A22" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationSummaryOfStockBasedCompensationAssociatedWithEachTypeOfAwardDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_60E5EB6E13D7549FB4F84505B842F28C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EECDFF449C0D506A8130545E924E345B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_60E5EB6E13D7549FB4F84505B842F28C" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EECDFF449C0D506A8130545E924E345B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_06EA1C4CFCE35E6C968D4108D297FC4F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EECDFF449C0D506A8130545E924E345B" xlink:to="loc_us-gaap_AwardTypeAxis_06EA1C4CFCE35E6C968D4108D297FC4F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B5E60C969A47CEC35CB9670201896125_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_06EA1C4CFCE35E6C968D4108D297FC4F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B5E60C969A47CEC35CB9670201896125_BA9240D2EEE85AEE8FEB50F919316A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E8068AD3EBE45962BCC466BE35D91E24" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_06EA1C4CFCE35E6C968D4108D297FC4F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E8068AD3EBE45962BCC466BE35D91E24" xlink:type="arc" />
    <loc xlink:href="enph-20160331.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_90C2AA41E283536EBF95F18A1E1EE102" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E8068AD3EBE45962BCC466BE35D91E24" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_90C2AA41E283536EBF95F18A1E1EE102" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_1E2EF898762C5AA283746F66CE20702C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E8068AD3EBE45962BCC466BE35D91E24" xlink:to="loc_us-gaap_EmployeeStockMember_1E2EF898762C5AA283746F66CE20702C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_4CBAC65BE66B57F690376AC553B1BCA0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_60E5EB6E13D7549FB4F84505B842F28C" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_4CBAC65BE66B57F690376AC553B1BCA0" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationSummaryOfStockOptionActivityDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationSummaryOfWeightedAverageGrantDateFairValueOfOptionsGrantedDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062088EED390A766D6773162077A6FE" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8B45D08EBEF5B89FA04173162077B95D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062088EED390A766D6773162077A6FE" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8B45D08EBEF5B89FA04173162077B95D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_277EBD29EA243DEFCF1A73162077FC0E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8B45D08EBEF5B89FA04173162077B95D" xlink:to="loc_us-gaap_AwardTypeAxis_277EBD29EA243DEFCF1A73162077FC0E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_F023C0AD74F3B25C72437316207730D2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_277EBD29EA243DEFCF1A73162077FC0E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_F023C0AD74F3B25C72437316207730D2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_F023C0AD74F3B25C72437316207730D2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_277EBD29EA243DEFCF1A73162077FC0E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_F023C0AD74F3B25C72437316207730D2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_0B75CEAFE3700C30BB1973162077F6FD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_F023C0AD74F3B25C72437316207730D2" xlink:to="loc_us-gaap_EmployeeStockOptionMember_0B75CEAFE3700C30BB1973162077F6FD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062088EED390A766D6773162077A6FE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_D9FCF9079C5631B564E973162077256B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_D9FCF9079C5631B564E973162077256B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_2EE6A4472B874495C45573162077842B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_2EE6A4472B874495C45573162077842B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_15A7189ECEBBCB57DA6B731620778A62" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_15A7189ECEBBCB57DA6B731620778A62" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_5837580FCE407A4C29E97316207746F2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_5837580FCE407A4C29E97316207746F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_846A5A53058830AD091F731620772178" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_47DFD2938A1C3EEFB2C0731620773027" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_846A5A53058830AD091F731620772178" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligations" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligationsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductWarrantyLiabilityLineItems" xlink:label="loc_us-gaap_ProductWarrantyLiabilityLineItems_EDBDA2435B92060D56F530937A51A6CE" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductWarrantyLiabilityTable" xlink:label="loc_us-gaap_ProductWarrantyLiabilityTable_9A2249DA03C2FC243A3630937A4F2D96" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_EDBDA2435B92060D56F530937A51A6CE" xlink:to="loc_us-gaap_ProductWarrantyLiabilityTable_9A2249DA03C2FC243A3630937A4F2D96" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6182A2284678FD3C881130937A50B07E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ProductWarrantyLiabilityTable_9A2249DA03C2FC243A3630937A4F2D96" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6182A2284678FD3C881130937A50B07E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_13E39B9D327B10CBE74A30937A5072A2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6182A2284678FD3C881130937A50B07E" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_13E39B9D327B10CBE74A30937A5072A2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_13E39B9D327B10CBE74A30937A5072A2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6182A2284678FD3C881130937A50B07E" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_13E39B9D327B10CBE74A30937A5072A2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_6A85174761E155C29AC130937A503E01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_13E39B9D327B10CBE74A30937A5072A2" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_6A85174761E155C29AC130937A503E01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_1F1F1173BE40F35B26CD30937A5131AC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ProductWarrantyLiabilityTable_9A2249DA03C2FC243A3630937A4F2D96" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_1F1F1173BE40F35B26CD30937A5131AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_71CB993B37650674DE6630937A5191C9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_1F1F1173BE40F35B26CD30937A5131AC" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_71CB993B37650674DE6630937A5191C9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_71CB993B37650674DE6630937A5191C9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_1F1F1173BE40F35B26CD30937A5131AC" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_71CB993B37650674DE6630937A5191C9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_4693786DF18882D8E7C830937A51EE35" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_71CB993B37650674DE6630937A5191C9" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_4693786DF18882D8E7C830937A51EE35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7AF7FD6A90DB79F4101730937A51ED2E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ProductWarrantyLiabilityTable_9A2249DA03C2FC243A3630937A4F2D96" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7AF7FD6A90DB79F4101730937A51ED2E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7940857CB928F75F967430937A5130EB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7AF7FD6A90DB79F4101730937A51ED2E" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7940857CB928F75F967430937A5130EB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7940857CB928F75F967430937A5130EB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7AF7FD6A90DB79F4101730937A51ED2E" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7940857CB928F75F967430937A5130EB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_4AFD7ABF1B80EBC2BC9130937A513923" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7940857CB928F75F967430937A5130EB" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_4AFD7ABF1B80EBC2BC9130937A513923" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProductWarrantyAccrual" xlink:label="loc_us-gaap_ProductWarrantyAccrual_A8C0619FC48BB2AA2CFD30937A5139A8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_EDBDA2435B92060D56F530937A51A6CE" xlink:to="loc_us-gaap_ProductWarrantyAccrual_A8C0619FC48BB2AA2CFD30937A5139A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_124386A9D9FCA694509730937A51C629" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_EDBDA2435B92060D56F530937A51A6CE" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_124386A9D9FCA694509730937A51C629" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligationsSummaryOfWarrantyActivitiesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligationsTables" xlink:type="extended" />
</linkbase>
