<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2019-05-07T03:22:15.6570594+00:00 -->
<!-- Version            : 3.4.7044.22220 -->
<!-- Package ID         : 11aed7bed9074aca8aa5fc75691be8d4 -->
<!-- Copyright (c) 2019 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:us-types="http://fasb.org/us-types/2018-01-31" xmlns:stpr="http://xbrl.sec.gov/stpr/2018-01-31" xmlns:srt-types="http://fasb.org/srt-types/2018-01-31" xmlns:naics="http://xbrl.sec.gov/naics/2017-01-31" xmlns:invest="http://xbrl.sec.gov/invest/2013-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:srt="http://fasb.org/srt/2018-01-31" xmlns:us-gaap="http://fasb.org/us-gaap/2018-01-31" xmlns:dei="http://xbrl.sec.gov/dei/2018-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:country="http://xbrl.sec.gov/country/2017-01-31" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:currency="http://xbrl.sec.gov/currency/2017-01-31" xmlns:rgnx="http://regenxbio.com/20190331" xmlns:exch="http://xbrl.sec.gov/exch/2018-01-31" xmlns:sic="http://xbrl.sec.gov/sic/2011-01-31" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://regenxbio.com/20190331" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance" />
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase" />
  <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd" namespace="http://xbrl.sec.gov/dei/2018-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd" namespace="http://fasb.org/us-gaap/2018-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd" namespace="http://fasb.org/srt/2018-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/us-gaap/2018/elts/us-types-2018-01-31.xsd" namespace="http://fasb.org/us-types/2018-01-31" />
  <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/numeric" />
  <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/non-numeric" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/srt/2018/elts/srt-types-2018-01-31.xsd" namespace="http://fasb.org/srt-types/2018-01-31" />
  <xsd:import schemaLocation="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd" namespace="http://xbrl.sec.gov/country/2017-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/currency/2017/currency-2017-01-31.xsd" namespace="http://xbrl.sec.gov/currency/2017-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/exch/2018/exch-2018-01-31.xsd" namespace="http://xbrl.sec.gov/exch/2018-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd" namespace="http://xbrl.sec.gov/invest/2013-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/naics/2017/naics-2017-01-31.xsd" namespace="http://xbrl.sec.gov/naics/2017-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" namespace="http://xbrl.sec.gov/sic/2011-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd" namespace="http://xbrl.sec.gov/stpr/2018-01-31" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:roleType id="TemplateLink" roleURI="http://regenxbio.com/20190331/role/TemplateLink" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>00000 - Document - Template Link</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="rgnx-20190331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:title="Calculation Links, all" xlink:type="simple" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="rgnx-20190331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="rgnx-20190331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Label Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="rgnx-20190331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/StatementConsolidatedBalanceSheets" id="Role_StatementConsolidatedBalanceSheets">
        <link:definition>100010 - Statement - Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/StatementConsolidatedBalanceSheetsParenthetical" id="Role_StatementConsolidatedBalanceSheetsParenthetical">
        <link:definition>100020 - Statement - Consolidated Balance Sheets (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/StatementConsolidatedStatementsOfOperationsAndComprehensiveIncomeLoss" id="Role_StatementConsolidatedStatementsOfOperationsAndComprehensiveIncomeLoss">
        <link:definition>100030 - Statement - Consolidated Statements of Operations and Comprehensive Income (Loss)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/StatementConsolidatedStatementsOfStockholdersEquity" id="Role_StatementConsolidatedStatementsOfStockholdersEquity">
        <link:definition>100040 - Statement - Consolidated Statements of Stockholders&apos; Equity</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/StatementConsolidatedStatementsOfCashFlows" id="Role_StatementConsolidatedStatementsOfCashFlows">
        <link:definition>100050 - Statement - Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNatureOfBusiness" id="Role_DisclosureNatureOfBusiness">
        <link:definition>100060 - Disclosure - Nature of Business</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies" id="Role_DisclosureSummaryOfSignificantAccountingPolicies">
        <link:definition>100070 - Disclosure - Summary of Significant Accounting Policies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureMarketableSecurities" id="Role_DisclosureMarketableSecurities">
        <link:definition>100080 - Disclosure - Marketable Securities</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureFairValueOfFinancialInstruments" id="Role_DisclosureFairValueOfFinancialInstruments">
        <link:definition>100090 - Disclosure - Fair Value of Financial Instruments</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosurePropertyAndEquipmentNet" id="Role_DisclosurePropertyAndEquipmentNet">
        <link:definition>100100 - Disclosure - Property and Equipment, Net</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingencies" id="Role_DisclosureCommitmentsAndContingencies">
        <link:definition>100110 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenue" id="Role_DisclosureLicenseRevenue">
        <link:definition>100120 - Disclosure - License Revenue</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensation" id="Role_DisclosureStockBasedCompensation">
        <link:definition>100130 - Disclosure - Stock-based Compensation</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureIncomeTaxes" id="Role_DisclosureIncomeTaxes">
        <link:definition>100140 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureRelatedPartyTransactions" id="Role_DisclosureRelatedPartyTransactions">
        <link:definition>100150 - Disclosure - Related Party Transactions</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNetIncomeLossPerShare" id="Role_DisclosureNetIncomeLossPerShare">
        <link:definition>100160 - Disclosure - Net Income (Loss) Per Share</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSupplementalDisclosures" id="Role_DisclosureSupplementalDisclosures">
        <link:definition>100170 - Disclosure - Supplemental Disclosures</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies">
        <link:definition>100180 - Disclosure - Summary of Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesTables" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesTables">
        <link:definition>100190 - Disclosure - Summary of Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureMarketableSecuritiesTables" id="Role_DisclosureMarketableSecuritiesTables">
        <link:definition>100200 - Disclosure - Marketable Securities (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsTables" id="Role_DisclosureFairValueOfFinancialInstrumentsTables">
        <link:definition>100210 - Disclosure - Fair Value of Financial Instruments (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosurePropertyAndEquipmentNetTables" id="Role_DisclosurePropertyAndEquipmentNetTables">
        <link:definition>100220 - Disclosure - Property and Equipment, Net (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesTables" id="Role_DisclosureCommitmentsAndContingenciesTables">
        <link:definition>100230 - Disclosure - Commitments and Contingencies (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenueTables" id="Role_DisclosureLicenseRevenueTables">
        <link:definition>100240 - Disclosure - License Revenue (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationTables" id="Role_DisclosureStockBasedCompensationTables">
        <link:definition>100250 - Disclosure - Stock-based Compensation (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNetIncomeLossPerShareTables" id="Role_DisclosureNetIncomeLossPerShareTables">
        <link:definition>100260 - Disclosure - Net Income (Loss) Per Share (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSupplementalDisclosuresTables" id="Role_DisclosureSupplementalDisclosuresTables">
        <link:definition>100270 - Disclosure - Supplemental Disclosures (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNatureOfBusinessAdditionalInformationDetail" id="Role_DisclosureNatureOfBusinessAdditionalInformationDetail">
        <link:definition>100280 - Disclosure - Nature of Business - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesSummaryOfReconciliationOfCashAndCashEquivalentsAndRestrictedCashDetail" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesSummaryOfReconciliationOfCashAndCashEquivalentsAndRestrictedCashDetail">
        <link:definition>100290 - Disclosure - Summary of Significant Accounting Policies - Summary of Reconciliation of Cash and Cash Equivalents and Restricted Cash (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail">
        <link:definition>100300 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureMarketableSecuritiesSummaryOfCompanyMarketableSecuritiesDetail" id="Role_DisclosureMarketableSecuritiesSummaryOfCompanyMarketableSecuritiesDetail">
        <link:definition>100310 - Disclosure - Marketable Securities - Summary of Company Marketable Securities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureMarketableSecuritiesAdditionalInformationDetail" id="Role_DisclosureMarketableSecuritiesAdditionalInformationDetail">
        <link:definition>100320 - Disclosure - Marketable Securities - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureMarketableSecuritiesSummaryOfFairValuesAndUnrealizedLossesOfMarketableSecuritiesHeldByCompanyInUnrealizedLossPositionForLessThan12MonthsAnd12MonthsOrGreaterDetail" id="Role_DisclosureMarketableSecuritiesSummaryOfFairValuesAndUnrealizedLossesOfMarketableSecuritiesHeldByCompanyInUnrealizedLossPositionForLessThan12MonthsAnd12MonthsOrGreaterDetail">
        <link:definition>100330 - Disclosure - Marketable Securities - Summary of Fair Values and Unrealized Losses of Marketable Securities Held by the Company in an Unrealized Loss Position for Less Than 12 months and 12 Months or Greater (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfFairValueOfCashEquivalentsAndMarketableSecuritiesDetail" id="Role_DisclosureFairValueOfFinancialInstrumentsScheduleOfFairValueOfCashEquivalentsAndMarketableSecuritiesDetail">
        <link:definition>100340 - Disclosure - Fair Value of Financial Instruments - Schedule of Fair Value of Cash Equivalents and Marketable Securities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsAdditionalInformationDetail" id="Role_DisclosureFairValueOfFinancialInstrumentsAdditionalInformationDetail">
        <link:definition>100350 - Disclosure - Fair Value of Financial Instruments - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosurePropertyAndEquipmentNetScheduleOfPropertyAndEquipmentDetail" id="Role_DisclosurePropertyAndEquipmentNetScheduleOfPropertyAndEquipmentDetail">
        <link:definition>100360 - Disclosure - Property and Equipment Net - Schedule of Property and Equipment (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosurePropertyAndEquipmentNetAdditionalInformationDetail" id="Role_DisclosurePropertyAndEquipmentNetAdditionalInformationDetail">
        <link:definition>100370 - Disclosure - Property and Equipment Net - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetail" id="Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetail">
        <link:definition>100380 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesSummaryOfLeaseCostsAndSupplementalCashFlowInformationOfOperatingLeasesDetail" id="Role_DisclosureCommitmentsAndContingenciesSummaryOfLeaseCostsAndSupplementalCashFlowInformationOfOperatingLeasesDetail">
        <link:definition>100390 - Disclosure - Commitments and Contingencies - Summary of Lease Costs and Supplemental Cash Flow Information of Operating Leases (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesWeightedAverageRemainingLeaseTermAndWeightedAverageDiscountRateOfOperatingLeasesDetail" id="Role_DisclosureCommitmentsAndContingenciesWeightedAverageRemainingLeaseTermAndWeightedAverageDiscountRateOfOperatingLeasesDetail">
        <link:definition>100400 - Disclosure - Commitments and Contingencies - Weighted-Average Remaining Lease Term and Weighted-Average Discount Rate of Operating Leases (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesReconciliationOfUndiscountedFutureMinimumLeasePaymentsRemainingUnder9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail" id="Role_DisclosureCommitmentsAndContingenciesReconciliationOfUndiscountedFutureMinimumLeasePaymentsRemainingUnder9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail">
        <link:definition>100410 - Disclosure - Commitments and Contingencies - Reconciliation of Undiscounted Future Minimum Lease Payments Remaining Under 9800 Medical Center Drive Lease and Other Operating Leases (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesReconciliationOfUndiscountedFutureMinimumLeasePaymentsRemainingUnder9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail2" id="Role_DisclosureCommitmentsAndContingenciesReconciliationOfUndiscountedFutureMinimumLeasePaymentsRemainingUnder9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail2">
        <link:definition>100420 - Disclosure - Commitments and Contingencies - Reconciliation of Undiscounted Future Minimum Lease Payments Remaining Under 9800 Medical Center Drive Lease and Other Operating Leases (Detail)2</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfFutureMinimumLeasePaymentsUnderTopic840For9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail" id="Role_DisclosureCommitmentsAndContingenciesScheduleOfFutureMinimumLeasePaymentsUnderTopic840For9800MedicalCenterDriveLeaseAndOtherOperatingLeasesDetail">
        <link:definition>100430 - Disclosure - Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Topic 840 for 9800 Medical Center Drive Lease and Other Operating Leases (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenueAdditionalInformationDetail" id="Role_DisclosureLicenseRevenueAdditionalInformationDetail">
        <link:definition>100440 - Disclosure - License Revenue - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenueSummaryOfChangesInBalancesOfReceivablesContractAssetsAndContractLiabilitiesDetail" id="Role_DisclosureLicenseRevenueSummaryOfChangesInBalancesOfReceivablesContractAssetsAndContractLiabilitiesDetail">
        <link:definition>100450 - Disclosure - License Revenue - Summary of Changes in Balances of Receivables, Contract Assets and Contract Liabilities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenueAdditionalInformationDetail1" id="Role_DisclosureLicenseRevenueAdditionalInformationDetail1">
        <link:definition>100460 - Disclosure - License Revenue - Additional Information (Detail1)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureLicenseRevenueAdditionalInformationDetail1Default" id="Role_DisclosureLicenseRevenueAdditionalInformationDetail1Default">
        <link:definition>100460 - Disclosure - License Revenue - Additional Information (Detail1)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationAdditionalInformationDetail" id="Role_DisclosureStockBasedCompensationAdditionalInformationDetail">
        <link:definition>100470 - Disclosure - Stock-based Compensation - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationStockBasedCompensationExpenseByAwardTypeDetail" id="Role_DisclosureStockBasedCompensationStockBasedCompensationExpenseByAwardTypeDetail">
        <link:definition>100480 - Disclosure - Stock-based Compensation - Stock-Based Compensation Expense by Award Type (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationStockBasedCompensationExpenseDetail" id="Role_DisclosureStockBasedCompensationStockBasedCompensationExpenseDetail">
        <link:definition>100490 - Disclosure - Stock-based Compensation - Stock-Based Compensation Expense (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationSummaryOfStockOptionActivityDetail" id="Role_DisclosureStockBasedCompensationSummaryOfStockOptionActivityDetail">
        <link:definition>100500 - Disclosure - Stock-based Compensation - Summary of Stock Option Activity (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureStockBasedCompensationSummaryOfUnvestedRsusActivityUnder2015PlanDetail" id="Role_DisclosureStockBasedCompensationSummaryOfUnvestedRsusActivityUnder2015PlanDetail">
        <link:definition>100510 - Disclosure - Stock-based Compensation - Summary of Unvested RSUs Activity Under 2015 Plan (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail" id="Role_DisclosureIncomeTaxesAdditionalInformationDetail">
        <link:definition>100520 - Disclosure - Income Taxes - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureRelatedPartyTransactionsAdditionalInformationDetail" id="Role_DisclosureRelatedPartyTransactionsAdditionalInformationDetail">
        <link:definition>100530 - Disclosure - Related Party Transactions - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNetIncomeLossPerShareComputationsOfBasicAndDilutedNetIncomeLossPerShareDetail" id="Role_DisclosureNetIncomeLossPerShareComputationsOfBasicAndDilutedNetIncomeLossPerShareDetail">
        <link:definition>100540 - Disclosure - Net Income (Loss) Per Share - Computations of Basic and Diluted Net Income (Loss) Per Share (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureNetIncomeLossPerShareSchedulesForComputationOfDilutedWeightedAverageSharesOutstandingDetail" id="Role_DisclosureNetIncomeLossPerShareSchedulesForComputationOfDilutedWeightedAverageSharesOutstandingDetail">
        <link:definition>100550 - Disclosure - Net Income (Loss) Per Share - Schedules for Computation of Diluted Weighted-Average Shares Outstanding (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSupplementalDisclosuresSchedulesOfAccruedExpensesAndOtherCurrentLiabilitiesDetail" id="Role_DisclosureSupplementalDisclosuresSchedulesOfAccruedExpensesAndOtherCurrentLiabilitiesDetail">
        <link:definition>100560 - Disclosure - Supplemental Disclosures - Schedules of Accrued Expenses and Other Current Liabilities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://regenxbio.com/20190331/taxonomy/role/DisclosureSupplementalDisclosuresAdditionalInformationDetail" id="Role_DisclosureSupplementalDisclosuresAdditionalInformationDetail">
        <link:definition>100570 - Disclosure - Supplemental Disclosures - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="rgnx_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_AccruedExpensesAndOtherCurrentLiabilities" name="AccruedExpensesAndOtherCurrentLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_InterestIncomeFromLicencing" name="InterestIncomeFromLicencing" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_AccountingStandardsUpdate201802Member" name="AccountingStandardsUpdate201802Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_ImputedInterestIncomeFromLicensing" name="ImputedInterestIncomeFromLicensing" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_IncreaseDecreaseInOperatingLeaseRightOfUseAssets" name="IncreaseDecreaseInOperatingLeaseRightOfUseAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_IncreaseDecreaseInOperatingLeaseLiabilities" name="IncreaseDecreaseInOperatingLeaseLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_IncreaseDecreaseInDeferredRentPayable" name="IncreaseDecreaseInDeferredRentPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_LicenseAgreementRevenueRecognitionTextBlock" name="LicenseAgreementRevenueRecognitionTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LicenseAgreementRevenueRecognitionAbstract" name="LicenseAgreementRevenueRecognitionAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_ScheduleOfCashAndCashEquivalentsAndRestrictedCashTableTextBlock" name="ScheduleOfCashAndCashEquivalentsAndRestrictedCashTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_SummaryOfLeaseCostsAndSupplementalCashFlowInformationOfOperatingLeasesTableTextBlock" name="SummaryOfLeaseCostsAndSupplementalCashFlowInformationOfOperatingLeasesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_ScheduleOfLesseeOperatingLeaseWeightedAverageRemainingLeaseTermAndWeightedAverageDiscountRate" name="ScheduleOfLesseeOperatingLeaseWeightedAverageRemainingLeaseTermAndWeightedAverageDiscountRate" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_SummaryOfChangesInReceivablesAndContractAssetsAndContractLiabilitiesTableTextBlock" name="SummaryOfChangesInReceivablesAndContractAssetsAndContractLiabilitiesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_TwoThousandFourteenAndTwoThousandFifteenEquityIncentivePlanMember" name="TwoThousandFourteenAndTwoThousandFifteenEquityIncentivePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_SignificantAccountingPoliciesLineItems" name="SignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_SignificantAccountingPoliciesTable" name="SignificantAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NineThousandEightHundredMedicalCenterDriveMember" name="NineThousandEightHundredMedicalCenterDriveMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_TaxCutsAndJobsActReclassificationFromAOCIToRetainedEarningsTaxEffect" name="TaxCutsAndJobsActReclassificationFromAOCIToRetainedEarningsTaxEffect" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_AvailableForSaleDebtSecuritiesRemainingMaturitiesGreaterThanThreeYears" name="AvailableForSaleDebtSecuritiesRemainingMaturitiesGreaterThanThreeYears" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_CashEquivalentsAndMarketableSecuritiesMember" name="CashEquivalentsAndMarketableSecuritiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NonMarketableEquitySecuritiesCarryingValue" name="NonMarketableEquitySecuritiesCarryingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_RemeasurementsOrImpairmentLossesOnNonMarketableEquitySecurities" name="RemeasurementsOrImpairmentLossesOnNonMarketableEquitySecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_LesseeOperatingLeaseNumberOfSquareFeetToBeConstructed" name="LesseeOperatingLeaseNumberOfSquareFeetToBeConstructed" type="num:areaItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_TenantImprovementAllowanceToBeReceived" name="TenantImprovementAllowanceToBeReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_MinimumRequiredLeaseTermToUseOptionalTerminationOfLease" name="MinimumRequiredLeaseTermToUseOptionalTerminationOfLease" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_PercentageOfEarlyTerminationFee" name="PercentageOfEarlyTerminationFee" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_TermOfRequiredBaseRentToBePaidAsTerminationFee" name="TermOfRequiredBaseRentToBePaidAsTerminationFee" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LesseeOperatingLeasePeriodicPaymentTermAfterTheCommencement" name="LesseeOperatingLeasePeriodicPaymentTermAfterTheCommencement" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LesseeOperatingLeaseFrequencyOfPeriodicPayment" name="LesseeOperatingLeaseFrequencyOfPeriodicPayment" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_NineThousandSevenHundredTwelveMedicalCenterDriveMember" name="NineThousandSevenHundredTwelveMedicalCenterDriveMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NineThousandSixHundredBlackwellRoadMember" name="NineThousandSixHundredBlackwellRoadMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_MarylandAndNewYorkMember" name="MarylandAndNewYorkMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_UniversityOfPennsylvaniaMember" name="UniversityOfPennsylvaniaMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_EuropeanPatentOfficeProceedingMember" name="EuropeanPatentOfficeProceedingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_LesseeOperatingLeaseLeaseNotYetCommencedAdditionalAreaLeased" name="LesseeOperatingLeaseLeaseNotYetCommencedAdditionalAreaLeased" type="num:areaItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_ChangeInTenantImprovementAllowance" name="ChangeInTenantImprovementAllowance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_LesseeOperatingLeaseIncreasedOnFutureRent" name="LesseeOperatingLeaseIncreasedOnFutureRent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_LeaseCommencedDate" name="LeaseCommencedDate" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LeasePaymentsCommencementPeriod" name="LeasePaymentsCommencementPeriod" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_RequiredPeriodToTerminateLeaseAfterCommencementPeriod" name="RequiredPeriodToTerminateLeaseAfterCommencementPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_OperatingLeaseExpirationYear" name="OperatingLeaseExpirationYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_OtherPropertiesHeldUnderOperatingLeasesMember" name="OtherPropertiesHeldUnderOperatingLeasesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_OtherOperatingLeasesMember" name="OtherOperatingLeasesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_UpfrontFeePayable" name="UpfrontFeePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_NumberOfDevelopmentPartneredProductCandidates" name="NumberOfDevelopmentPartneredProductCandidates" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="rgnx_NumberOfTechnologyLicensees" name="NumberOfTechnologyLicensees" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LicenseRevenueLineItems" name="LicenseRevenueLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_LicenseRevenueTable" name="LicenseRevenueTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NAVTechnologyLicenseesMember" name="NAVTechnologyLicenseesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NAVTechnologyPlatformMember" name="NAVTechnologyPlatformMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_JanuaryTwoZeroOneEightAmendmentAgreementMember" name="JanuaryTwoZeroOneEightAmendmentAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_AveXisIncorporationMember" name="AveXisIncorporationMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_LicenseAgreementMember" name="LicenseAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_NovemberTwoThousandEighteenLicenseAgreementMember" name="NovemberTwoThousandEighteenLicenseAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_AbeonaTherapeuticsIncorporationMember" name="AbeonaTherapeuticsIncorporationMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_MarchTwoZeroOneFourLicenseAgreementMember" name="MarchTwoZeroOneFourLicenseAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_FirstAnniversaryMember" name="FirstAnniversaryMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_SecondAnniversaryMember" name="SecondAnniversaryMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_SalesBasedMilestonesMember" name="SalesBasedMilestonesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_MilestoneFeePaymentsUponCommencementOfClinicalTrials" name="MilestoneFeePaymentsUponCommencementOfClinicalTrials" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_MilestoneFeePaymentsUponSubmissionOfRegulatoryApprovalFilings" name="MilestoneFeePaymentsUponSubmissionOfRegulatoryApprovalFilings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_MilestoneFeePaymentsUponApprovalOfCommercialProducts" name="MilestoneFeePaymentsUponApprovalOfCommercialProducts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_MilestoneFeePaymentsUponAchievementOfSpecifiedSalesTargets" name="MilestoneFeePaymentsUponAchievementOfSpecifiedSalesTargets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_ReceivablesAndContractAssetsAbstract" name="ReceivablesAndContractAssetsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_IncreaseDecreaseInAccountsReceivableCurrentAndNoncurrent" name="IncreaseDecreaseInAccountsReceivableCurrentAndNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_IncreaseDecreaseInContractWithCustomerAssetCurrent" name="IncreaseDecreaseInContractWithCustomerAssetCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_UpfrontLicenseFeePaid" name="UpfrontLicenseFeePaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_MilestoneFeePaymentsUponAchievementOfVariousDevelopmentAndCommercialization" name="MilestoneFeePaymentsUponAchievementOfVariousDevelopmentAndCommercialization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_LicenseAgreementPeriod" name="LicenseAgreementPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LicenseAgreementAmendmentDate" name="LicenseAgreementAmendmentDate" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_LicenseFees" name="LicenseFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_MilestonePayments" name="MilestonePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_UnpaidMilestonePayments" name="UnpaidMilestonePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_TransactionPriceOfLicense" name="TransactionPriceOfLicense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_PaymentsForRemainingDevelopmentMilestones" name="PaymentsForRemainingDevelopmentMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_SalesBasedMilestonePaymentExcludeTransactionPrice" name="SalesBasedMilestonePaymentExcludeTransactionPrice" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_ConsiderationPaymentDuePeriodOne" name="ConsiderationPaymentDuePeriodOne" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_ConsiderationPaymentDuePeriodTwo" name="ConsiderationPaymentDuePeriodTwo" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="rgnx_IncreaseInTransactionPriceOfLicense" name="IncreaseInTransactionPriceOfLicense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="rgnx_TwoThousandAndFifteenEquityIncentivePlanMember" name="TwoThousandAndFifteenEquityIncentivePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_TwoThousandFifteenEmployeeStockPurchasePlanMember" name="TwoThousandFifteenEmployeeStockPurchasePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_IncomeTaxDisclosureLineItems" name="IncomeTaxDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_IncomeTaxDisclosureTable" name="IncomeTaxDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_AccruedExpensesAndOtherCurrentLiabilitiesMember" name="AccruedExpensesAndOtherCurrentLiabilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_FOXKISERLimitedLiabilityPartnershipMember" name="FOXKISERLimitedLiabilityPartnershipMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="rgnx_AccruedExternalResearchAndDevelopmentExpenses" name="AccruedExternalResearchAndDevelopmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_AccruedLicensingCosts" name="AccruedLicensingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_AccruedExternalGeneralAndAdministrativeExpenses" name="AccruedExternalGeneralAndAdministrativeExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="rgnx_AccruedPurchasesOfPropertyAndEquipment" name="AccruedPurchasesOfPropertyAndEquipment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
</xsd:schema>
