-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 DttlgYWmb4CRdjQKSyypWYzqPRD6FZ7KIBgbbC3seBS3QWxMuy2TVb5EwYxB0hcM
 9WGyhQsyWLEpbJDqo9up0g==

<SEC-DOCUMENT>0001140361-10-041983.txt : 20101022
<SEC-HEADER>0001140361-10-041983.hdr.sgml : 20101022
<ACCEPTANCE-DATETIME>20101022143847
ACCESSION NUMBER:		0001140361-10-041983
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101026
FILED AS OF DATE:		20101022
DATE AS OF CHANGE:		20101022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROETT RIORDAN
		CENTRAL INDEX KEY:			0001090084

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-22444
		FILM NUMBER:		101137075

	MAIL ADDRESS:	
		STREET 1:		JOHN HOPKINS UNIVERSITY
		STREET 2:		1740 MASSACHUSETTS AVE
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20036

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Western Asset High Yield Defined Opportunity Fund Inc.
		CENTRAL INDEX KEY:			0001497186
		IRS NUMBER:				273075810
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		55 WATER STREET
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10041
		BUSINESS PHONE:		888-777-0102

	MAIL ADDRESS:	
		STREET 1:		55 WATER STREET
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10041
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2010-10-26</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001497186</issuerCik>
        <issuerName>Western Asset High Yield Defined Opportunity Fund Inc.</issuerName>
        <issuerTradingSymbol>HYI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001090084</rptOwnerCik>
            <rptOwnerName>ROETT RIORDAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>620 EIGHTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>49TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10018</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person does not beneficially own any securities of the issuer, directly or indirectly.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ William J. Renahan by Power of Attorney for Dr. Riordan Roett</signatureName>
        <signatureDate>2010-10-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----