<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with WebFilings-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://enphase.com/role/CommitmentsAndContingencies" xlink:href="enph-20130331.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnaudited" xlink:href="enph-20130331.xsd#CondensedConsolidatedBalanceSheetsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:href="enph-20130331.xsd#CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:href="enph-20130331.xsd#CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:href="enph-20130331.xsd#CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:href="enph-20130331.xsd#CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/DocumentAndEntityInformation" xlink:href="enph-20130331.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurements" xlink:href="enph-20130331.xsd#FairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsDetails" xlink:href="enph-20130331.xsd#FairValueMeasurementsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsDetailsTextual" xlink:href="enph-20130331.xsd#FairValueMeasurementsDetailsTextual" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/FairValueMeasurementsTables" xlink:href="enph-20130331.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/IncomeTaxes" xlink:href="enph-20130331.xsd#IncomeTaxes" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/IncomeTaxesDetails" xlink:href="enph-20130331.xsd#IncomeTaxesDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/Inventory" xlink:href="enph-20130331.xsd#Inventory" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/InventoryDetails" xlink:href="enph-20130331.xsd#InventoryDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/InventoryTables" xlink:href="enph-20130331.xsd#InventoryTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/LongTermDebt" xlink:href="enph-20130331.xsd#LongTermDebt" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/LongTermDebtDetails" xlink:href="enph-20130331.xsd#LongTermDebtDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/LongTermDebtDetailsTextual" xlink:href="enph-20130331.xsd#LongTermDebtDetailsTextual" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/LongTermDebtTables" xlink:href="enph-20130331.xsd#LongTermDebtTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholders" xlink:href="enph-20130331.xsd#NetLossPerShareAttributableToCommonStockholders" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersDetails" xlink:href="enph-20130331.xsd#NetLossPerShareAttributableToCommonStockholdersDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersDetailsTextual" xlink:href="enph-20130331.xsd#NetLossPerShareAttributableToCommonStockholdersDetailsTextual" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersTables" xlink:href="enph-20130331.xsd#NetLossPerShareAttributableToCommonStockholdersTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/OverviewAndSummaryOfAccountingPoliciesDetails" xlink:href="enph-20130331.xsd#OverviewAndSummaryOfAccountingPoliciesDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/OverviewAndSummaryOfSignificantAccountingPolicies" xlink:href="enph-20130331.xsd#OverviewAndSummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/OverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:href="enph-20130331.xsd#OverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensation" xlink:href="enph-20130331.xsd#StockBasedCompensation" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:href="enph-20130331.xsd#StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationDetailsTextual" xlink:href="enph-20130331.xsd#StockBasedCompensationDetailsTextual" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationExpenseByAwardTypeDetails" xlink:href="enph-20130331.xsd#StockBasedCompensationExpenseByAwardTypeDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:href="enph-20130331.xsd#StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:href="enph-20130331.xsd#StockBasedCompensationStockOptionActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationTables" xlink:href="enph-20130331.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:href="enph-20130331.xsd#StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligations" xlink:href="enph-20130331.xsd#WarrantyObligations" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligationsDetails" xlink:href="enph-20130331.xsd#WarrantyObligationsDetails" xlink:type="simple" />
  <roleRef roleURI="http://enphase.com/role/WarrantyObligationsTables" xlink:href="enph-20130331.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">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_DCCB361354395DE471A57F7F5CF1B8B8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_40332315405A17BD1FAA7F7F5CF11292" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_DCCB361354395DE471A57F7F5CF1B8B8" xlink:to="loc_us-gaap_StatementTable_40332315405A17BD1FAA7F7F5CF11292" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_935758FF6B7B02D29B127F8B7E49698C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_40332315405A17BD1FAA7F7F5CF11292" xlink:to="loc_us-gaap_StatementScenarioAxis_935758FF6B7B02D29B127F8B7E49698C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_153068C40EFE2C6C4FF17F8B7E4F1B79_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_935758FF6B7B02D29B127F8B7E49698C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_153068C40EFE2C6C4FF17F8B7E4F1B79_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_153068C40EFE2C6C4FF17F8B7E4F1B79" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_935758FF6B7B02D29B127F8B7E49698C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_153068C40EFE2C6C4FF17F8B7E4F1B79" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DCCB361354395DE471A57F7F5CF1B8B8" xlink:to="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:to="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_BCBB0FC2A6A9A6AD39F87F7F5CF2FB0A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_BCBB0FC2A6A9A6AD39F87F7F5CF2FB0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_BBE2F28BE8CC8508018E7F7F5CF29C22" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_BBE2F28BE8CC8508018E7F7F5CF29C22" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_8E3AEA39437FDD4D74FF7F7F5CF210C6" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:to="loc_us-gaap_InventoryNet_8E3AEA39437FDD4D74FF7F7F5CF210C6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_0B5E58AB91743FD54D1A7F7F5CF2655A" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_0B5E58AB91743FD54D1A7F7F5CF2655A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_CBEEDE0957EE0BB07D7E7F7F5CF28B10" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_CAC1F655B672F6727CD47F7F5CF2C114" xlink:to="loc_us-gaap_AssetsCurrent_CBEEDE0957EE0BB07D7E7F7F5CF28B10" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_D2033EEF9DB1D23B29A67F7F5CF27E91" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_D2033EEF9DB1D23B29A67F7F5CF27E91" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_514DF086B16B303CBAE57F7F5CF29A12" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_514DF086B16B303CBAE57F7F5CF29A12" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_96C52470C395C36A78B27F7F5CF28FE2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_949AC83B80EEC6DD5B2E7F7F5CF2D616" xlink:to="loc_us-gaap_Assets_96C52470C395C36A78B27F7F5CF28FE2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DCCB361354395DE471A57F7F5CF1B8B8" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_BEFD9942601F96E4D4777F7F5CF3BD10" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:to="loc_us-gaap_AccountsPayableCurrent_BEFD9942601F96E4D4777F7F5CF3BD10" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_F717B8EF0E6BBC4CC01D7F7F5CF3B881" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_F717B8EF0E6BBC4CC01D7F7F5CF3B881" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_E799E7E07EEB729B70527F7F5CF397E8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:to="loc_us-gaap_DeferredRevenueCurrent_E799E7E07EEB729B70527F7F5CF397E8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LoansPayableCurrent" xlink:label="loc_us-gaap_LoansPayableCurrent_B7A08F9F28BD454347AC7F7F5CF37844" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:to="loc_us-gaap_LoansPayableCurrent_B7A08F9F28BD454347AC7F7F5CF37844" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_84B6E023E69F4411E7977F7F5CF37DF1" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3B98F467C078641AE0FD7F7F5CF255A4" xlink:to="loc_us-gaap_LiabilitiesCurrent_84B6E023E69F4411E7977F7F5CF37DF1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_71D3ADC2F0D3503FD2687F7F5CF3E34D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_71D3ADC2F0D3503FD2687F7F5CF3E34D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductWarrantyAccrualNoncurrent" xlink:label="loc_us-gaap_ProductWarrantyAccrualNoncurrent_CBEDC52ED8F22A62957E7F7F5CF33B0A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:to="loc_us-gaap_ProductWarrantyAccrualNoncurrent_CBEDC52ED8F22A62957E7F7F5CF33B0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_0A539A9B0E01ACA7ECCB7F7F5CF32E08" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_0A539A9B0E01ACA7ECCB7F7F5CF32E08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermLoansPayable" xlink:label="loc_us-gaap_LongTermLoansPayable_D58FF8758CFDA354CD1E7F7F5CF30EF2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_1D2F5569CD42D17C71897F7F5CF35123" xlink:to="loc_us-gaap_LongTermLoansPayable_D58FF8758CFDA354CD1E7F7F5CF30EF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_59CE20577CDE52A963DA7F7F5CF32493" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_Liabilities_59CE20577CDE52A963DA7F7F5CF32493" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_EFBD7FB7C06C233E27FB7F7F5CF31EA2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_CommitmentsAndContingencies_EFBD7FB7C06C233E27FB7F7F5CF31EA2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_1D552CADD180A38B943B7F7F5CF42D99" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_PreferredStockValue_1D552CADD180A38B943B7F7F5CF42D99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_B776E20006F26EAE5D0C7F7F5CF497F3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_CommonStockValue_B776E20006F26EAE5D0C7F7F5CF497F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_820C5CED8CF56D1628977F7F5CF4E743" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_AdditionalPaidInCapital_820C5CED8CF56D1628977F7F5CF4E743" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_7329D35CF1A1FE3006D07F7F5CF42F97" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_7329D35CF1A1FE3006D07F7F5CF42F97" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_D870B9DBF67AA7CC41447F7F5CF45AF3" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_D870B9DBF67AA7CC41447F7F5CF45AF3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_AEF32AA5E5338FE63D287F7F5CF4D1D8" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_83B520EB3919E209A13C7F7F5CF39B5F" xlink:to="loc_us-gaap_StockholdersEquity_AEF32AA5E5338FE63D287F7F5CF4D1D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_DDAE492704A624F040F07F7F5CF40941" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_0B316715A4F203FFC90C7F7F5CF2DA3D" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_DDAE492704A624F040F07F7F5CF40941" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_4FE561CCF86B464D0E3380C33887EB07" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_StatementTable_4FE561CCF86B464D0E3380C33887EB07" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_ABCFF0C75EC026CDA3E680C338873DCC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4FE561CCF86B464D0E3380C33887EB07" xlink:to="loc_us-gaap_StatementScenarioAxis_ABCFF0C75EC026CDA3E680C338873DCC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_EEF8C192058D15CC666880C3388715C3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_ABCFF0C75EC026CDA3E680C338873DCC" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_EEF8C192058D15CC666880C3388715C3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_EEF8C192058D15CC666880C3388715C3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_ABCFF0C75EC026CDA3E680C338873DCC" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_EEF8C192058D15CC666880C3388715C3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_19769EA89796A8E4DC1180C33887D632" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_19769EA89796A8E4DC1180C33887D632" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_3FA314B80C22C993C02880C338872C57" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_3FA314B80C22C993C02880C338872C57" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_0CB4EC281827ECE1B70980C338872799" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_0CB4EC281827ECE1B70980C338872799" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_FEB2A93A1713E4A9626180C33887F501" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_CommonStockSharesIssued_FEB2A93A1713E4A9626180C33887F501" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_917FFC9586C4729DDA7280C338876FFE" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_917FFC9586C4729DDA7280C338876FFE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_A06115D3C4757B89AA3080C33887076A" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_A06115D3C4757B89AA3080C33887076A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_FA5ADD592B40549F60A480C338872180" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_FA5ADD592B40549F60A480C338872180" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_4B32F8644705E75CBB9880C3388761D8" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_PreferredStockSharesIssued_4B32F8644705E75CBB9880C3388761D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_1912121E864B6B2EC41980C338886367" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F5D3F59FCF7EA8EA974080C338877ED3" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_1912121E864B6B2EC41980C338886367" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_B97E37B1FAAA9E417B69806A2C72AF13" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_StatementTable_B97E37B1FAAA9E417B69806A2C72AF13" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_434519A8A7C7803FCA76806A2C724B96" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_B97E37B1FAAA9E417B69806A2C72AF13" xlink:to="loc_us-gaap_StatementScenarioAxis_434519A8A7C7803FCA76806A2C724B96" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_B649B44E5C7A250AD390806A2C72E727_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_434519A8A7C7803FCA76806A2C724B96" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_B649B44E5C7A250AD390806A2C72E727_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_B649B44E5C7A250AD390806A2C72E727" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_434519A8A7C7803FCA76806A2C724B96" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_B649B44E5C7A250AD390806A2C72E727" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_47E439B1BFDA8B68A9A1806A2C727D43" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_47E439B1BFDA8B68A9A1806A2C727D43" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_3DA2A66DD9C7C2071A3D806A2C72903C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_47E439B1BFDA8B68A9A1806A2C727D43" xlink:to="loc_us-gaap_NetIncomeLoss_3DA2A66DD9C7C2071A3D806A2C72903C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_47E439B1BFDA8B68A9A1806A2C727D43" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_40949E30899EBFFCFD1F806A2C729358" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_40949E30899EBFFCFD1F806A2C729358" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_14412B4C49C7C897AAD3806A2C7319EF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_14412B4C49C7C897AAD3806A2C7319EF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_2A7FA0FAF0E1F0B8BE45806A2C7368F0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_ShareBasedCompensation_2A7FA0FAF0E1F0B8BE45806A2C7368F0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_E6549ECFBCD6851ACBBF806A2C73CE34" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_E6549ECFBCD6851ACBBF806A2C73CE34" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingAssetsAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_9B249C2EBBB703D96180806A2C73C365" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_9B249C2EBBB703D96180806A2C73C365" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_665EFA09F57C946ED22E806A2C739AB0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_665EFA09F57C946ED22E806A2C739AB0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_675DF9FF4F84A15C7DD5806A2C737F3F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_675DF9FF4F84A15C7DD5806A2C737F3F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_A9CCC7133D8CB0A279A1806A2C73FC83" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_A9CCC7133D8CB0A279A1806A2C73FC83" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_660EDE9F58B8259E1A2B806A2C73E499" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_980E65DC3EF787A943E8806A2C732A22" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_660EDE9F58B8259E1A2B806A2C73E499" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3774639ACBD65C8FAB41806A2C73F46E" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_AF02465DD20C2593F97D806A2C721D5B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3774639ACBD65C8FAB41806A2C73F46E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4D0B5DE9CA70909B1FC2806A2C73BE08" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4D0B5DE9CA70909B1FC2806A2C73BE08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_B1795D3554FC825885BD806A2C731392" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4D0B5DE9CA70909B1FC2806A2C73BE08" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_B1795D3554FC825885BD806A2C731392" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_FDB87D25435514CFAD26806A2C7388CB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4D0B5DE9CA70909B1FC2806A2C73BE08" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_FDB87D25435514CFAD26806A2C7388CB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_1479B41E4B4D38EAA0A2806A2C735EE7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_1479B41E4B4D38EAA0A2806A2C735EE7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_F9BC8C9BFF32E692BE68806A2C745659" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_F9BC8C9BFF32E692BE68806A2C745659" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:label="loc_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_DF9E3761F8CA8F21B69C806A2C74C54C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_DF9E3761F8CA8F21B69C806A2C74C54C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_A0ACEDC6477424DF25D8806A2C74D5E6" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_A0ACEDC6477424DF25D8806A2C74D5E6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_E8155142BFFCCF2DE931806A2C749874" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_E8155142BFFCCF2DE931806A2C749874" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_78AA999A049EBD4688CD806A2C748C8E" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5B75A37B61BDCF469478806A2C73E67A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_78AA999A049EBD4688CD806A2C748C8E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_1D17577B0098A0C2CCC5806A2C74BD9F" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_1D17577B0098A0C2CCC5806A2C74BD9F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_2938C8B74B49BE255FD5806A2C74C474" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_2938C8B74B49BE255FD5806A2C74C474" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_44915CFA65AD45516833806A2C748181" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_44915CFA65AD45516833806A2C748181" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_205EBAE10A3E2EED789A806A2C74CD84" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_205EBAE10A3E2EED789A806A2C74CD84" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_B98BB7C93EE6B8F5E197806A2C74C616" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_205EBAE10A3E2EED789A806A2C74CD84" xlink:to="loc_us-gaap_InterestPaid_B98BB7C93EE6B8F5E197806A2C74C616" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:label="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_105ADE244F42BD143311806A2C746BDE" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4E2A4440FD7B5113A41C806A2C721AC7" xlink:to="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_105ADE244F42BD143311806A2C746BDE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_CA2CF9564F86D2C10578806A2C743F82" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_105ADE244F42BD143311806A2C746BDE" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_CA2CF9564F86D2C10578806A2C743F82" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_OfferingCostsNotYetPaid" xlink:label="loc_enph_OfferingCostsNotYetPaid_397A902D014D075B48B7806A2C741075" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_105ADE244F42BD143311806A2C746BDE" xlink:to="loc_enph_OfferingCostsNotYetPaid_397A902D014D075B48B7806A2C741075" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfComprehensiveLossUnaudited" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_A1F767F23D520C87D27C7F7F5CDCDFB8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_4E68DEB44A638C635D257F7F5CDB8358" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_A1F767F23D520C87D27C7F7F5CDCDFB8" xlink:to="loc_us-gaap_StatementTable_4E68DEB44A638C635D257F7F5CDB8358" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_1FDCDF5D6829185C4E707F7F5CDB88B3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4E68DEB44A638C635D257F7F5CDB8358" xlink:to="loc_us-gaap_StatementScenarioAxis_1FDCDF5D6829185C4E707F7F5CDB88B3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_BF19F9CFB887E5D818987F7F5CDCE352_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_1FDCDF5D6829185C4E707F7F5CDB88B3" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_BF19F9CFB887E5D818987F7F5CDCE352_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_BF19F9CFB887E5D818987F7F5CDCE352" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_1FDCDF5D6829185C4E707F7F5CDB88B3" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_BF19F9CFB887E5D818987F7F5CDCE352" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_7FA9D0DDD35D4F9823A37F7F5CDC8630" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A1F767F23D520C87D27C7F7F5CDCDFB8" xlink:to="loc_us-gaap_NetIncomeLoss_7FA9D0DDD35D4F9823A37F7F5CDC8630" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4462C6F33F73BBFF43EF7F7F5CDC7027" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A1F767F23D520C87D27C7F7F5CDCDFB8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4462C6F33F73BBFF43EF7F7F5CDC7027" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_234097CEFDE2AEC38BDE7F7F5CDC1EF4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4462C6F33F73BBFF43EF7F7F5CDC7027" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_234097CEFDE2AEC38BDE7F7F5CDC1EF4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_5DD5D2C2D03A6713B22F7F7F5CDC7354" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A1F767F23D520C87D27C7F7F5CDCDFB8" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_5DD5D2C2D03A6713B22F7F7F5CDC7354" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/CondensedConsolidatedStatementsOfOperationsUnaudited" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_EE97FD22BD281130408E7F7F5CE21974" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_StatementTable_EE97FD22BD281130408E7F7F5CE21974" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_1C1F0F53AE85B116AB767F7F5CE2FB7B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_EE97FD22BD281130408E7F7F5CE21974" xlink:to="loc_us-gaap_StatementScenarioAxis_1C1F0F53AE85B116AB767F7F5CE2FB7B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DA19C282F45A23A8DC197F7F5CE29107_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_1C1F0F53AE85B116AB767F7F5CE2FB7B" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DA19C282F45A23A8DC197F7F5CE29107_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DA19C282F45A23A8DC197F7F5CE29107" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_1C1F0F53AE85B116AB767F7F5CE2FB7B" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DA19C282F45A23A8DC197F7F5CE29107" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_3F8B5D1FD12507D1C1F47F7F5CE25B63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_SalesRevenueNet_3F8B5D1FD12507D1C1F47F7F5CE25B63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaap_CostOfRevenue_068A4F819615B44A64F67F7F5CE242B6" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_CostOfRevenue_068A4F819615B44A64F67F7F5CE242B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_77FA8995CC362465F0C17F7F5CE2B93F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_GrossProfit_77FA8995CC362465F0C17F7F5CE2B93F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_56593A0572415D47531A7F7F5CE2A1B6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_56593A0572415D47531A7F7F5CE2A1B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_A1259C9AA2DF70CCAD817F7F5CE22A05" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:to="loc_us-gaap_SellingAndMarketingExpense_A1259C9AA2DF70CCAD817F7F5CE22A05" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_08A2AACD8847B1B77EDA7F7F5CE33AE9" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_08A2AACD8847B1B77EDA7F7F5CE33AE9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_55452E0EA79D43028C6F7F7F5CE38F2C" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_35B848958133E719310B7F7F5CE24DFD" xlink:to="loc_us-gaap_OperatingExpenses_55452E0EA79D43028C6F7F7F5CE38F2C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_4C04F8182D013A3569927F7F5CE33047" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_4C04F8182D013A3569927F7F5CE33047" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_F31AAAC2393A855AD1357F7F5CE3811C" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_F31AAAC2393A855AD1357F7F5CE3811C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_C239F46A4968464240A07F7F5CE36AE7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_F31AAAC2393A855AD1357F7F5CE3811C" xlink:to="loc_us-gaap_InterestExpense_C239F46A4968464240A07F7F5CE36AE7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_6068FA042531592FC25C7F7F5CE3D26C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_F31AAAC2393A855AD1357F7F5CE3811C" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_6068FA042531592FC25C7F7F5CE3D26C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_1A9940272B7334FDD3C77F7F5CE30115" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpenseAbstract_F31AAAC2393A855AD1357F7F5CE3811C" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_1A9940272B7334FDD3C77F7F5CE30115" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_14197DDBFF760AF85A647F7F5CE3119E" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_14197DDBFF760AF85A647F7F5CE3119E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_486AE554C1F46730545A7F7F5CE3DC00" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_486AE554C1F46730545A7F7F5CE3DC00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_CFCCF013F0C7424C23DF7F7F5CE37D64" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_NetIncomeLoss_CFCCF013F0C7424C23DF7F7F5CE37D64" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare_30FB5E07CDCFFE7A30477F7F5CE3243C" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicAndDilutedShare_30FB5E07CDCFFE7A30477F7F5CE3243C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_8BCEC77ACC2A5F1E59837F7F5CE3490A" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_92E80BA2966FF0D932E97F7F5CE28EFA" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_8BCEC77ACC2A5F1E59837F7F5CE3490A" xlink:type="arc" />
  </definitionLink>
  <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/FairValueMeasurementsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0CEB99630ACD60FC2EC27B0874D63DE0" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0133EE5FAB6B7AF3F18C7B0874C7EBF0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0CEB99630ACD60FC2EC27B0874D63DE0" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0133EE5FAB6B7AF3F18C7B0874C7EBF0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DAA2297F6526358F7F817B0874CEEA8C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0133EE5FAB6B7AF3F18C7B0874C7EBF0" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DAA2297F6526358F7F817B0874CEEA8C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_C3563FEEC0A160524DA87B0874CFDEA8_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DAA2297F6526358F7F817B0874CEEA8C" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_C3563FEEC0A160524DA87B0874CFDEA8_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_C3563FEEC0A160524DA87B0874CFDEA8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DAA2297F6526358F7F817B0874CEEA8C" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_C3563FEEC0A160524DA87B0874CFDEA8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_C579389048797F8795207B098DE30ED4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_C3563FEEC0A160524DA87B0874CFDEA8" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_C579389048797F8795207B098DE30ED4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4703F4A3085AC08072437B0874CF4A5C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0133EE5FAB6B7AF3F18C7B0874C7EBF0" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4703F4A3085AC08072437B0874CF4A5C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21F18159C4B4D4D9C5267B0874D650DE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4703F4A3085AC08072437B0874CF4A5C" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21F18159C4B4D4D9C5267B0874D650DE_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21F18159C4B4D4D9C5267B0874D650DE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_4703F4A3085AC08072437B0874CF4A5C" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21F18159C4B4D4D9C5267B0874D650DE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_FDEE8F879F38C96C2E9F7B09B6945A78" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21F18159C4B4D4D9C5267B0874D650DE" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_FDEE8F879F38C96C2E9F7B09B6945A78" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_316542F8FEAA58B6C42E7B10B3A56A1B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0CEB99630ACD60FC2EC27B0874D63DE0" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_316542F8FEAA58B6C42E7B10B3A56A1B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyContractAssetFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_FC3310146C1A6BBCBB177B0BD5B2C299" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_316542F8FEAA58B6C42E7B10B3A56A1B" xlink:to="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_FC3310146C1A6BBCBB177B0BD5B2C299" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_EB447D1581602B089D9E7B10EF00661B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0CEB99630ACD60FC2EC27B0874D63DE0" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_EB447D1581602B089D9E7B10EF00661B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_3F1F1DC21D603345F2B87AE074C250CA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_EB447D1581602B089D9E7B10EF00661B" xlink:to="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_3F1F1DC21D603345F2B87AE074C250CA" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsDetailsTextual" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_4E9D7A6ED14ACBF47492806A2C4B3FDA" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_4226805DAB27F42D81D3806A2C4A49F6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_4E9D7A6ED14ACBF47492806A2C4B3FDA" xlink:to="loc_us-gaap_DerivativeTable_4226805DAB27F42D81D3806A2C4A49F6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_9BC3761A5170967FDF4A806A2C4A572F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_4226805DAB27F42D81D3806A2C4A49F6" xlink:to="loc_us-gaap_HedgingDesignationAxis_9BC3761A5170967FDF4A806A2C4A572F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_658652E3D4B305DEBAF7806A2C4A9F9E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_9BC3761A5170967FDF4A806A2C4A572F" xlink:to="loc_us-gaap_HedgingDesignationDomain_658652E3D4B305DEBAF7806A2C4A9F9E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_658652E3D4B305DEBAF7806A2C4A9F9E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_9BC3761A5170967FDF4A806A2C4A572F" xlink:to="loc_us-gaap_HedgingDesignationDomain_658652E3D4B305DEBAF7806A2C4A9F9E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_04941A603A28BFB0798F806A2C4ACF46" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_658652E3D4B305DEBAF7806A2C4A9F9E" xlink:to="loc_us-gaap_NondesignatedMember_04941A603A28BFB0798F806A2C4ACF46" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_2831AE7CBBA05B33C56E806A2C4A8C1F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_4226805DAB27F42D81D3806A2C4A49F6" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_2831AE7CBBA05B33C56E806A2C4A8C1F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_A62DEDDD09A1ADECB839806A2C4AC413_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2831AE7CBBA05B33C56E806A2C4A8C1F" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_A62DEDDD09A1ADECB839806A2C4AC413_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_A62DEDDD09A1ADECB839806A2C4AC413" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2831AE7CBBA05B33C56E806A2C4A8C1F" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_A62DEDDD09A1ADECB839806A2C4AC413" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_FF0841EB171846120693806A2C4B18D8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_A62DEDDD09A1ADECB839806A2C4AC413" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_FF0841EB171846120693806A2C4B18D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotionalAmountOfForeignCurrencyDerivatives" xlink:label="loc_us-gaap_NotionalAmountOfForeignCurrencyDerivatives_26D69FC61098E635DFE2806A2C4B7048" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_4E9D7A6ED14ACBF47492806A2C4B3FDA" xlink:to="loc_us-gaap_NotionalAmountOfForeignCurrencyDerivatives_26D69FC61098E635DFE2806A2C4B7048" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments" xlink:label="loc_us-gaap_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments_23BFAE81659ABDC37651806A2C4BA4F3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_4E9D7A6ED14ACBF47492806A2C4B3FDA" xlink:to="loc_us-gaap_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments_23BFAE81659ABDC37651806A2C4BA4F3" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/IncomeTaxes" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/IncomeTaxesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/Inventory" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/InventoryDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/InventoryTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/LongTermDebt" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/LongTermDebtDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_762389170C19934F536280C3384E4F49" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_87C774415777437EEFB480C3384D5597" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_762389170C19934F536280C3384E4F49" xlink:to="loc_us-gaap_DebtInstrumentTable_87C774415777437EEFB480C3384D5597" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_DADF2186441F5B15745A80C3384E14A5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_87C774415777437EEFB480C3384D5597" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_DADF2186441F5B15745A80C3384E14A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_DADF2186441F5B15745A80C3384E14A5" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_DADF2186441F5B15745A80C3384E14A5" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_81BDF86593DF39426DBC80C3384EC7DD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871" xlink:to="loc_us-gaap_SecuredDebtMember_81BDF86593DF39426DBC80C3384EC7DD" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_EquipmentFinancingFacilityMember" xlink:label="loc_enph_EquipmentFinancingFacilityMember_BC28686D8BCA108A30A080C3384E2081" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_741441290C5347DFC9C580C3384E6871" xlink:to="loc_enph_EquipmentFinancingFacilityMember_BC28686D8BCA108A30A080C3384E2081" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtCurrentAndNoncurrentAbstract" xlink:label="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_315B64E7A30C6CF00BA380C3384E84C4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_762389170C19934F536280C3384E4F49" xlink:to="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_315B64E7A30C6CF00BA380C3384E84C4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_B50F16A0892778CB54F080C3384E326A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_315B64E7A30C6CF00BA380C3384E84C4" xlink:to="loc_us-gaap_LongTermDebt_B50F16A0892778CB54F080C3384E326A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_A1E8DBCD7AB93AB2E01880C3384E7CD5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_315B64E7A30C6CF00BA380C3384E84C4" xlink:to="loc_us-gaap_LongTermDebtCurrent_A1E8DBCD7AB93AB2E01880C3384E7CD5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_D20CC77C6133DA8570B480C3384EB940" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_315B64E7A30C6CF00BA380C3384E84C4" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_D20CC77C6133DA8570B480C3384EB940" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_804528F5A3AE1B8631CA80C3384E9828" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_762389170C19934F536280C3384E4F49" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_804528F5A3AE1B8631CA80C3384E9828" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/LongTermDebtDetailsTextual" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_F4DF409E51ECD83C7ED67B0307FA3404" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_C98D02B993B57F8AD6FA7B0307F99A1D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F4DF409E51ECD83C7ED67B0307FA3404" xlink:to="loc_us-gaap_DebtInstrumentTable_C98D02B993B57F8AD6FA7B0307F99A1D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_52557A1F8E4168B913147B0307F93A87" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_C98D02B993B57F8AD6FA7B0307F99A1D" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_52557A1F8E4168B913147B0307F93A87" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_52557A1F8E4168B913147B0307F93A87" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_52557A1F8E4168B913147B0307F93A87" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_WellsFargoBankMember" xlink:label="loc_enph_WellsFargoBankMember_047A67DC2A5C9DA153A37B0307F9C459" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7" xlink:to="loc_enph_WellsFargoBankMember_047A67DC2A5C9DA153A37B0307F9C459" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_HerculesTechnologyGrowthCapitalIncMember" xlink:label="loc_enph_HerculesTechnologyGrowthCapitalIncMember_2C14928AC2B0FF4700D37B15659B008B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_C86B28618E7CE399AC5D7B0307F9BFF7" xlink:to="loc_enph_HerculesTechnologyGrowthCapitalIncMember_2C14928AC2B0FF4700D37B15659B008B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_67EE57289845FFE4C66A7B0307F9611D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_C98D02B993B57F8AD6FA7B0307F99A1D" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_67EE57289845FFE4C66A7B0307F9611D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_67EE57289845FFE4C66A7B0307F9611D" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_67EE57289845FFE4C66A7B0307F9611D" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_B841D8242C8E9FD9D5177B0307FA4BFC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_B841D8242C8E9FD9D5177B0307FA4BFC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_B5B5055940274FC353447B0307FA3C86" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20" xlink:to="loc_us-gaap_SecuredDebtMember_B5B5055940274FC353447B0307FA3C86" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_EquipmentFinancingFacilityMember" xlink:label="loc_enph_EquipmentFinancingFacilityMember_609162A616F1325723DE7B1CF5F1A629" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_EE684F1AFF3D48120A2F7B0307FA7E20" xlink:to="loc_enph_EquipmentFinancingFacilityMember_609162A616F1325723DE7B1CF5F1A629" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_LineOfCreditNumberOfDebtAgreements" xlink:label="loc_enph_LineOfCreditNumberOfDebtAgreements_DCFC9F66A176D94715397B1F72205DF9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F4DF409E51ECD83C7ED67B0307FA3404" xlink:to="loc_enph_LineOfCreditNumberOfDebtAgreements_DCFC9F66A176D94715397B1F72205DF9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_AF864CD2E42253AA94B27B0307FA0B99" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F4DF409E51ECD83C7ED67B0307FA3404" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_AF864CD2E42253AA94B27B0307FA0B99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentIncreaseAdditionalBorrowings" xlink:label="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_5D103048836DA715EBD97B0307FAF531" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F4DF409E51ECD83C7ED67B0307FA3404" xlink:to="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_5D103048836DA715EBD97B0307FAF531" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/LongTermDebtTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholders" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6986707775F05FBFA2E7103BA9A63426" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E404A5B762841965D900103BA9A69953" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6986707775F05FBFA2E7103BA9A63426" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E404A5B762841965D900103BA9A69953" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01F6963189C6C1FA54D7103BA9A6318F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E404A5B762841965D900103BA9A69953" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01F6963189C6C1FA54D7103BA9A6318F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01F6963189C6C1FA54D7103BA9A6318F" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01F6963189C6C1FA54D7103BA9A6318F" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_AAFE427A803579B0356C103BA9A65F3A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_us-gaap_StockOptionsMember_AAFE427A803579B0356C103BA9A65F3A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_EB975042F92A3423D86B103BA9A68A6D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_EB975042F92A3423D86B103BA9A68A6D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaap_WarrantMember_E7622E2F19AFE2D02314103BA9A64D98" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_us-gaap_WarrantMember_E7622E2F19AFE2D02314103BA9A64D98" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_WarrantConvertibleCommonStockMember" xlink:label="loc_enph_WarrantConvertibleCommonStockMember_2886A61EE6D1EE3B73A6103BA9A60D01" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_enph_WarrantConvertibleCommonStockMember_2886A61EE6D1EE3B73A6103BA9A60D01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertiblePreferredStockMember" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_59D624D832CEAF5B3BB8103BA9A6070F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_59D624D832CEAF5B3BB8103BA9A6070F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_C247F910079AA388BB13103BA9A6FF46" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_E715E04887737269F1DD103BA9A6B909" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_C247F910079AA388BB13103BA9A6FF46" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_AntidilutiveSecuritiesAbstract" xlink:label="loc_enph_AntidilutiveSecuritiesAbstract_B3301E7443DC5A47E749103BA9A63B01" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6986707775F05FBFA2E7103BA9A63426" xlink:to="loc_enph_AntidilutiveSecuritiesAbstract_B3301E7443DC5A47E749103BA9A63B01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_A8879324B395011B384F103BA9A68D32" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_AntidilutiveSecuritiesAbstract_B3301E7443DC5A47E749103BA9A63B01" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_A8879324B395011B384F103BA9A68D32" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersDetailsTextual" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/NetLossPerShareAttributableToCommonStockholdersTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/OverviewAndSummaryOfAccountingPoliciesDetails" xlink:type="extended">
    <loc xlink:href="enph-20130331.xsd#enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems" xlink:label="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:type="locator" />
    <loc xlink:href="enph-20130331.xsd#enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsTable" xlink:label="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsTable_B78A23732FFD2A50120A80C3386F3032" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsTable_B78A23732FFD2A50120A80C3386F3032" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9A3AD8CDCC93DB5057ED80C3386F2189" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsTable_B78A23732FFD2A50120A80C3386F3032" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9A3AD8CDCC93DB5057ED80C3386F2189" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_07DF8B989D6A612EFC0D80C3386F0969_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9A3AD8CDCC93DB5057ED80C3386F2189" xlink:to="loc_us-gaap_RelatedPartyDomain_07DF8B989D6A612EFC0D80C3386F0969_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_07DF8B989D6A612EFC0D80C3386F0969" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9A3AD8CDCC93DB5057ED80C3386F2189" xlink:to="loc_us-gaap_RelatedPartyDomain_07DF8B989D6A612EFC0D80C3386F0969" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_KpcbHoldingsIncMember" xlink:label="loc_enph_KpcbHoldingsIncMember_A40B92A2A66A7B1E69A780C3386F83F0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_07DF8B989D6A612EFC0D80C3386F0969" xlink:to="loc_enph_KpcbHoldingsIncMember_A40B92A2A66A7B1E69A780C3386F83F0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_E1A9EADB0DDA4DEB507B80C3386F090B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_E1A9EADB0DDA4DEB507B80C3386F090B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_F66731EB0E2422EAC58C80C33870B983" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_SharePrice_F66731EB0E2422EAC58C80C33870B983" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_3D03C1DA895AB7548E8D80C33870D526" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_3D03C1DA895AB7548E8D80C33870D526" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_UnderwritersDiscountsAndCommissions" xlink:label="loc_enph_UnderwritersDiscountsAndCommissions_3C1D974208494E6C8E7E80C33870EF9E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_enph_UnderwritersDiscountsAndCommissions_3C1D974208494E6C8E7E80C33870EF9E" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_OtherEstimatedOfferingCosts" xlink:label="loc_enph_OtherEstimatedOfferingCosts_7D79BBBBA689FE2943B380C33870F18E" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_enph_OtherEstimatedOfferingCosts_7D79BBBBA689FE2943B380C33870F18E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_D4FB9FA52867CDE1D41A80C33870039A" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_D4FB9FA52867CDE1D41A80C33870039A" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_ConversionOfConvertiblePreferredStockIntoCommonStock" xlink:label="loc_enph_ConversionOfConvertiblePreferredStockIntoCommonStock_0047FB0B1241E602E67680C33870F650" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_enph_ConversionOfConvertiblePreferredStockIntoCommonStock_0047FB0B1241E602E67680C33870F650" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleNotesPayable" xlink:label="loc_us-gaap_ConvertibleNotesPayable_A0D87FB44E2FA2A79E9F80C3387028A5" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_ConvertibleNotesPayable_A0D87FB44E2FA2A79E9F80C3387028A5" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_StockIssuedDuringPeriodSharesConversionOfConvertibleSecuritiesAndPaidInKindInterest" xlink:label="loc_enph_StockIssuedDuringPeriodSharesConversionOfConvertibleSecuritiesAndPaidInKindInterest_EDADDB65E0688A9EC78780C33870030B" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_enph_StockIssuedDuringPeriodSharesConversionOfConvertibleSecuritiesAndPaidInKindInterest_EDADDB65E0688A9EC78780C33870030B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_56F78D5390511FD79B7380C338709C1F" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_56F78D5390511FD79B7380C338709C1F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_0FF7B388A9D800790BEE80C33870C0FD" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_BasisOfPresentationConsolidationAndRelatedPartyTransactionsLineItems_F71FC305E433B13A7A2E80C3386F857F" xlink:to="loc_us-gaap_RevenueFromRelatedParties_0FF7B388A9D800790BEE80C33870C0FD" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/OverviewAndSummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/OverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensation" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationComponentsOfStockBasedCompensationExpenseByReportLineDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_D74A108DF0CBD8591A5A806A2C300CE8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_1EF75C30D270DE51A02D806A2C2FA3C2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_D74A108DF0CBD8591A5A806A2C300CE8" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_1EF75C30D270DE51A02D806A2C2FA3C2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_820E2BF8BB5C5E44C936806A2C2FFFAC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_1EF75C30D270DE51A02D806A2C2FA3C2" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_820E2BF8BB5C5E44C936806A2C2FFFAC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_820E2BF8BB5C5E44C936806A2C2FFFAC" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_820E2BF8BB5C5E44C936806A2C2FFFAC" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_A992C3970DDAF3F47C6A806A2C30D0FC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:to="loc_us-gaap_CostOfSalesMember_A992C3970DDAF3F47C6A806A2C30D0FC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_F6D754ABD0D7CED05D24806A2C308225" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_F6D754ABD0D7CED05D24806A2C308225" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_CD2F6CFEC69FF4CF2900806A2C30DC04" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_CD2F6CFEC69FF4CF2900806A2C30DC04" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_E9EB2073E71E9B81F3C7806A2C30E5F3" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_7E4360FA26E541FD2E4A806A2C2F49DF" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_E9EB2073E71E9B81F3C7806A2C30E5F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_85CEFFD0FCD1632465FB806A2C3030AA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_D74A108DF0CBD8591A5A806A2C300CE8" xlink:to="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_85CEFFD0FCD1632465FB806A2C3030AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_81CF97F5191B5998C509806A2C30604C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_85CEFFD0FCD1632465FB806A2C3030AA" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_81CF97F5191B5998C509806A2C30604C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationDetailsTextual" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationExpenseByAwardTypeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_A52311974E82424554CD806DC102A67C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EB4DBA6E4CCAD05742D9806DC1016D2D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_A52311974E82424554CD806DC102A67C" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EB4DBA6E4CCAD05742D9806DC1016D2D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_F8D5933099B765F8EB91806DC1010AC3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EB4DBA6E4CCAD05742D9806DC1016D2D" xlink:to="loc_us-gaap_AwardTypeAxis_F8D5933099B765F8EB91806DC1010AC3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_F8D5933099B765F8EB91806DC1010AC3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_F8D5933099B765F8EB91806DC1010AC3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5" xlink:type="arc" />
    <loc xlink:href="enph-20130331.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_D8BE6E841B5A11DCC33E806E86A329F6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_D8BE6E841B5A11DCC33E806E86A329F6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_61C5FA53F88FFBAE7BFA806E9E400352" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_04DDEE9AF9F38B05C327806DC10290D5" xlink:to="loc_us-gaap_EmployeeStockMember_61C5FA53F88FFBAE7BFA806E9E400352" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_FEEA316CD01528B48BA3806ECF27677C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_A52311974E82424554CD806DC102A67C" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_FEEA316CD01528B48BA3806ECF27677C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationRestrictedStockUnitActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D7BD5D690DAD68588A568078CC857F7B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F4C310240BC1A89966EE8078CC84A780" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D7BD5D690DAD68588A568078CC857F7B" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F4C310240BC1A89966EE8078CC84A780" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_245BC2CC524E456D4B2C8078CC844D91" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F4C310240BC1A89966EE8078CC84A780" xlink:to="loc_us-gaap_AwardTypeAxis_245BC2CC524E456D4B2C8078CC844D91" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_77ED76F3B2CBF150C7398078CC841413_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_245BC2CC524E456D4B2C8078CC844D91" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_77ED76F3B2CBF150C7398078CC841413_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_77ED76F3B2CBF150C7398078CC841413" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_245BC2CC524E456D4B2C8078CC844D91" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_77ED76F3B2CBF150C7398078CC841413" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_05C835E865DF75815169807960DA5E3D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_77ED76F3B2CBF150C7398078CC841413" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_05C835E865DF75815169807960DA5E3D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D7BD5D690DAD68588A568078CC857F7B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5A218F65FF9DB58632A9807ABF401B5C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5A218F65FF9DB58632A9807ABF401B5C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_6D0CA11B08AC23775041807B0001C6D0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_6D0CA11B08AC23775041807B0001C6D0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_72C756606B80F1E885A9807B21067E2E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_72C756606B80F1E885A9807B21067E2E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_834E7EA85411170C60D0807B396D4D80" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_C9246B331EF4E6C8C7CB807A54352637" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_834E7EA85411170C60D0807B396D4D80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D7BD5D690DAD68588A568078CC857F7B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_60EF08EAEB4964AF7D01807BFFA93D23" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_60EF08EAEB4964AF7D01807BFFA93D23" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_38B18A7E838869C6C9E5807C4DEEC7D9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_38B18A7E838869C6C9E5807C4DEEC7D9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_36D1260F72C63D924375807C828DA5AC" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_36D1260F72C63D924375807C828DA5AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_F29CB58723CD198A8BDA807CBC8EB324" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_D422FBCA28E27115730A807BA85A2FBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_F29CB58723CD198A8BDA807CBC8EB324" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationTables" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/StockBasedCompensationValuationAssumptionsOfStockOptionsUnderBlackScholesModelDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F5FC80D5992E18F4CEFC800338A18D03" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_47162600F49BDE50BA29800338A1FC08" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F5FC80D5992E18F4CEFC800338A18D03" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_47162600F49BDE50BA29800338A1FC08" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_DE05168678CA5AC6285A800338A11001" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_47162600F49BDE50BA29800338A1FC08" xlink:to="loc_us-gaap_AwardTypeAxis_DE05168678CA5AC6285A800338A11001" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_789AC6AF9D6421045233800338A19824_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_DE05168678CA5AC6285A800338A11001" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_789AC6AF9D6421045233800338A19824_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_789AC6AF9D6421045233800338A19824" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_DE05168678CA5AC6285A800338A11001" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_789AC6AF9D6421045233800338A19824" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_AE92C1F50E2B11F34D8080637EB82478" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_789AC6AF9D6421045233800338A19824" xlink:to="loc_us-gaap_StockOptionsMember_AE92C1F50E2B11F34D8080637EB82478" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_F5FC80D5992E18F4CEFC800338A18D03" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_934D3B3054706AB268AD800338A12902" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_934D3B3054706AB268AD800338A12902" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_0D6B00FBD5DF237BE66C800338A17810" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_0D6B00FBD5DF237BE66C800338A17810" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_2C3D4FEFB0C27E176866800338A15D25" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_2C3D4FEFB0C27E176866800338A15D25" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_CFAC7182828048802CE9800338A274DB" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_CFAC7182828048802CE9800338A274DB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6174CDBBF5CA36F88D268061A49255F1" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A0C5CFA7927D51FFAE65800338A1FA34" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6174CDBBF5CA36F88D268061A49255F1" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligations" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligationsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://enphase.com/role/WarrantyObligationsTables" xlink:type="extended" />
</linkbase>
