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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-29</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001359586</rptOwnerCik>
            <rptOwnerName>Foley Brendan P Jr</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>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP &amp; GEN. CONTROLLER</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2008-09-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14703</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>OPTION (RIGHT  TO PURCHASE)</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>28.705</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-09-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18178</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-09-29</value>
            </exerciseDate>
            <expirationDate>
                <value>2015-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>18178</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>OPTION (RIGHT  TO PURCHASE)</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>37.63</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-09-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6550</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-05-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6550</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F3">DISPOSITION WAS PURSUANT TO THE CONSUMMATION OF THE AGREEMENT AND PLAN OF MERGER, DATED AS OF APRIL 23, 2008, AMONG TRIARC COMPANIES, INC., GREEN MERGER SUB, INC. AND WENDY'S INTERNATIONAL, INC. (THE &quot;MERGER AGREEMENT&quot;).  UNDER THE MERGER AGREEMENT EACH OPTION TO PURCHASE A WENDY'S COMMON SHARE BECAME FULLY VESTED AND WAS CONVERTED TO AN OPTION TO PURCHASE 4.25 COMMON SHARES OF THE COMBINED COMPANY, WENDY'S/ARBY'S GROUP, INC., AS OF THE EFFECTIVE TIME OF THE MERGER, SEPTEMBER 29, 2008.  THE OPTION EXERCISE PRICE FOR EACH OPTION TO PURCHASE A WENDY'S COMMON SHARE WAS DIVIDED BY 4.25.  THE CLOSING PRICE OF WENDY'S COMMON SHARES WAS $19.21 PER SHARE ON THAT DATE.</footnote>
        <footnote id="F1">SHARES SHOWN ON TABLE 1 INCLUDE SHARES ACQUIRED PURSUANT TO THE DIVIDEND REINVESTMENT PROVISIONS OF RESTRICTED STOCK AND RESTRICTED STOCK UNIT AWARDS MADE UNDER THE ISSUER'S 2003 AND 2007 STOCK INCENTIVE PLANS.</footnote>
        <footnote id="F2">DISPOSITION WAS PURSUANT TO THE CONSUMMATION OF THE AGREEMENT AND PLAN OF MERGER, DATED AS OF APRIL 23, 2008, AMONG TRIARC COMPANIES, INC., GREEN MERGER SUB, INC. AND WENDY'S INTERNATIONAL, INC. (THE &quot;MERGER AGREEMENT&quot;).  UNDER THE MERGER AGREEMENT EACH WENDY'S COMMON SHARE BECAME FULLY VESTED AND WAS CONVERTED TO 4.25 COMMON SHARES OF THE COMBINED COMPANY, WENDY'S/ARBY'S GROUP, INC., AS OF THE EFFECTIVE TIME OF THE MERGER, SEPTEMBER 29, 2008.  THE CLOSING PRICE OF WENDY'S COMMON SHARES WAS $19.21 PER SHARE ON THAT DATE.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>DANA KLEIN, ATTORNEY-IN-FACT</signatureName>
        <signatureDate>2008-10-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0303
4
2008-09-29
1
0000105668
WENDYS INTERNATIONAL INC
WEN
0001359586
Foley Brendan P Jr
WENDY'S INTERNATIONAL, INC.
P. O. BOX 256
DUBLIN
OH
43017-0256
0
1
0
0
SVP & GEN. CONTROLLER
Common Stock
2008-09-29
4
D
0
14703
0
D
0
D
OPTION (RIGHT  TO PURCHASE)
28.705
2008-09-29
4
D
0
18178
0
D
2008-09-29
2015-04-30
Common Stock
18178
0
D
OPTION (RIGHT  TO PURCHASE)
37.63
2008-09-29
4
D
0
6550
0
D
2008-05-01
2014-04-30
Common Stock
6550
0
D
DISPOSITION WAS PURSUANT TO THE CONSUMMATION OF THE AGREEMENT AND PLAN OF MERGER, DATED AS OF APRIL 23, 2008, AMONG TRIARC COMPANIES, INC., GREEN MERGER SUB, INC. AND WENDY'S INTERNATIONAL, INC. (THE "MERGER AGREEMENT").  UNDER THE MERGER AGREEMENT EACH OPTION TO PURCHASE A WENDY'S COMMON SHARE BECAME FULLY VESTED AND WAS CONVERTED TO AN OPTION TO PURCHASE 4.25 COMMON SHARES OF THE COMBINED COMPANY, WENDY'S/ARBY'S GROUP, INC., AS OF THE EFFECTIVE TIME OF THE MERGER, SEPTEMBER 29, 2008.  THE OPTION EXERCISE PRICE FOR EACH OPTION TO PURCHASE A WENDY'S COMMON SHARE WAS DIVIDED BY 4.25.  THE CLOSING PRICE OF WENDY'S COMMON SHARES WAS $19.21 PER SHARE ON THAT DATE.
SHARES SHOWN ON TABLE 1 INCLUDE SHARES ACQUIRED PURSUANT TO THE DIVIDEND REINVESTMENT PROVISIONS OF RESTRICTED STOCK AND RESTRICTED STOCK UNIT AWARDS MADE UNDER THE ISSUER'S 2003 AND 2007 STOCK INCENTIVE PLANS.
DISPOSITION WAS PURSUANT TO THE CONSUMMATION OF THE AGREEMENT AND PLAN OF MERGER, DATED AS OF APRIL 23, 2008, AMONG TRIARC COMPANIES, INC., GREEN MERGER SUB, INC. AND WENDY'S INTERNATIONAL, INC. (THE "MERGER AGREEMENT").  UNDER THE MERGER AGREEMENT EACH WENDY'S COMMON SHARE BECAME FULLY VESTED AND WAS CONVERTED TO 4.25 COMMON SHARES OF THE COMBINED COMPANY, WENDY'S/ARBY'S GROUP, INC., AS OF THE EFFECTIVE TIME OF THE MERGER, SEPTEMBER 29, 2008.  THE CLOSING PRICE OF WENDY'S COMMON SHARES WAS $19.21 PER SHARE ON THAT DATE.
DANA KLEIN, ATTORNEY-IN-FACT
2008-10-01