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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-03-01</periodOfReport>

    <issuer>
        <issuerCik>0000105668</issuerCik>
        <issuerName>WENDYS INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>WEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227161</rptOwnerCik>
            <rptOwnerName>KIRWAN WILLIAM E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WENDY'S INTERNATIONAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>P. O. BOX 256</rptOwnerStreet2>
            <rptOwnerCity>DUBLIN</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>43017-0256</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>4841</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-03-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>320</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>58.385</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>320</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2453</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">EACH SHARE OF PHANTOM STOCK IS PAYABLE IN 1 SHARE OF COMMON STOCK OF THE ISSUER.</footnote>
        <footnote id="F2">REFLECTS SHARES ACQUIRED PURSUANT TO THE DIVIDEND REINVESTMENT PROVISIONS OF THE ISSUER'S DEFERRED COMPENSATION PLAN.</footnote>
        <footnote id="F3">REFLECTS PHANTOM STOCK ACQUIRED THROUGH PARTICIPATION IN ISSUER'S DEFERRED COMPENSATION PLAN.  PHANTOM STOCK IS PAYABLE IN COMMON STOCK NOT EARLIER THAN SIX MONTHS AFTER TERMINATION OF REPORTING PERSON'S SERVICE AS A DIRECTOR OF THE ISSUER.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>DANA KLEIN, ATTORNEY-IN-FACT</signatureName>
        <signatureDate>2006-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
