<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:68b506b5-78fe-4fe7-98a1-b49ea93b378e,g:b0079a32-7b0c-401a-a3dd-1bf876969ae3-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#PvpAdjustmentsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllAdjToCompMember" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#ecd_AllAdjToCompMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EquityAwardsFairValueAtFiscalYearMember_f5b97b7e-d686-4ff4-8724-1f0044c656cd" xlink:href="enph-20240404.xsd#enph_EquityAwardsFairValueAtFiscalYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_EquityAwardsFairValueAtFiscalYearMember_f5b97b7e-d686-4ff4-8724-1f0044c656cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EquityAwardsAdjustmentsMember_ab9cfd1c-86cd-4de0-aeb3-43808804b63d" xlink:href="enph-20240404.xsd#enph_EquityAwardsAdjustmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_EquityAwardsAdjustmentsMember_ab9cfd1c-86cd-4de0-aeb3-43808804b63d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PensionBenefitChangeInActuarialPresentValueMember_fb4b0f78-d39a-46e7-96f6-dca5bb1f3574" xlink:href="enph-20240404.xsd#enph_PensionBenefitChangeInActuarialPresentValueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_PensionBenefitChangeInActuarialPresentValueMember_fb4b0f78-d39a-46e7-96f6-dca5bb1f3574" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PensionBenefitAdjustmentMember_05954683-4dd6-496b-9085-ae1432ed7cf1" xlink:href="enph-20240404.xsd#enph_PensionBenefitAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_PensionBenefitAdjustmentMember_05954683-4dd6-496b-9085-ae1432ed7cf1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EquityAwardsFairGrantsDuringTheYearMember_56ccbe64-dbf2-4c9a-9d73-8e75a22950a1" xlink:href="enph-20240404.xsd#enph_EquityAwardsFairGrantsDuringTheYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_EquityAwardsFairGrantsDuringTheYearMember_56ccbe64-dbf2-4c9a-9d73-8e75a22950a1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EquityAwardsGrantedInPriorYearsUnvestedMember_63132575-cd47-44f8-a6fb-0467be4408e9" xlink:href="enph-20240404.xsd#enph_EquityAwardsGrantedInPriorYearsUnvestedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_EquityAwardsGrantedInPriorYearsUnvestedMember_63132575-cd47-44f8-a6fb-0467be4408e9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EquityAwardsGrantedInPriorYearsVestedMember_90e70c61-a555-41b5-ae05-957fc889def6" xlink:href="enph-20240404.xsd#enph_EquityAwardsGrantedInPriorYearsVestedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_enph_EquityAwardsGrantedInPriorYearsVestedMember_90e70c61-a555-41b5-ae05-957fc889def6" xlink:type="arc" order="7"/>
  </link:definitionLink>
</link:linkbase>
