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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-07-27</periodOfReport>

    <issuer>
        <issuerCik>0000097476</issuerCik>
        <issuerName>TEXAS INSTRUMENTS INC</issuerName>
        <issuerTradingSymbol>TXN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194832</rptOwnerCik>
            <rptOwnerName>ENGIBOUS THOMAS J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12500 TI BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75243</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman of the Board</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-07-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20996</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>29.46</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>102579</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>261.16</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust--401(k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17733.52</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust--PS</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F2">Estimated shares attributable to TI 401(k) Account as of 12-31-05.   (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in this account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.</footnote>
        <footnote id="F1">Withholding of shares of common stock to satisfy tax withholding obligation (relating to vesting of a previously granted award).</footnote>
        <footnote id="F3">Estimated shares attributable to TI Universal Profit Sharing account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>DANIEL M. DRORY, ATTORNEY IN FACT</signatureName>
        <signatureDate>2006-07-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-07-27
0000097476
TEXAS INSTRUMENTS INC
TXN
0001194832
ENGIBOUS THOMAS J
12500 TI BOULEVARD
DALLAS
TX
75243
1
1
0
0
Chairman of the Board
Common Stock
2006-07-27
4
F
0
20996
29.46
D
102579
D
Common Stock
261.16
I
By Trust--401(k)
Common Stock
17733.52
I
By Trust--PS
Estimated shares attributable to TI 401(k) Account as of 12-31-05.   (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in this account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.
Withholding of shares of common stock to satisfy tax withholding obligation (relating to vesting of a previously granted award).
Estimated shares attributable to TI Universal Profit Sharing account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.
DANIEL M. DRORY, ATTORNEY IN FACT
2006-07-28