<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-02-14</periodOfReport>

    <issuer>
        <issuerCik>0000899715</issuerCik>
        <issuerName>TANGER FACTORY OUTLET CENTERS INC</issuerName>
        <issuerTradingSymbol>SKT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001366740</rptOwnerCik>
            <rptOwnerName>Berman Bridget Ryan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2 BAILEYS MILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 718</rptOwnerStreet2>
            <rptOwnerCity>NEW VERNON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07976</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-02-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20096</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents grant of restricted shares approved by the Company's Board of Directors on February 14, 2012 under the Company's Amended and Restated Incentive Award Plan.  The restricted shares vest evenly over a three year period on December 31st of each year.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Joshua D. Cox, attorney-in-fact for Bridget Ryan Berman</signatureName>
        <signatureDate>2012-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
