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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Ol8WZh6YS/sfMy854jO0q8uRFZnK+JksYK/VZR5v/evBcbN6DGPv0YbXxbEXB0VR
 TJ0arbPrxTHzE+z4TYZVSg==

<SEC-DOCUMENT>0001319161-09-000005.txt : 20090316
<SEC-HEADER>0001319161-09-000005.hdr.sgml : 20090316
<ACCEPTANCE-DATETIME>20090316174601
ACCESSION NUMBER:		0001319161-09-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090315
FILED AS OF DATE:		20090316
DATE AS OF CHANGE:		20090316

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Grann Phyllis E
		CENTRAL INDEX KEY:			0001369909

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32502
		FILM NUMBER:		09685745

	MAIL ADDRESS:	
		STREET 1:		WARNER MUSIC GROUP
		STREET 2:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Warner Music Group Corp.
		CENTRAL INDEX KEY:			0001319161
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-AMUSEMENT & RECREATION SERVICES [7900]
		IRS NUMBER:				134271875
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019
		BUSINESS PHONE:		212-275-2000

	MAIL ADDRESS:	
		STREET 1:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WMG Parent Corp.
		DATE OF NAME CHANGE:	20050228
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-03-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001319161</issuerCik>
        <issuerName>Warner Music Group Corp.</issuerName>
        <issuerTradingSymbol>wmg</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001369909</rptOwnerCik>
            <rptOwnerName>Grann Phyllis E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WARNER MUSIC GROUP</rptOwnerStreet1>
            <rptOwnerStreet2>75 ROCKEFELLER PLAZA</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2009-03-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>34188</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.34</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>55661</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Common Stock granted pursuant to a Director Restricted Stock Award Agreement in accordance with the Company's currently established compensation policies with respect to independent directors.  Shares represent 50% of such director's annual director compensation based on a fair market value on the date of grant (calc. as the closing price on the grant date in accordance with the terms of the Company's Amended and Restated 2005 Omnibus Award Plan).  Shares will be delivered to reporting person upon vesting.  Shares vest on February 23, 2010, the one-year anniversary of the Company's Annual Meeting for the preceding fiscal year.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Trent N. Tappe as attorney-in-fact</signatureName>
        <signatureDate>2009-03-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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