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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-03-18</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191525</rptOwnerCik>
            <rptOwnerName>CARP DANIEL A</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>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>8664</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-03-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>227.5</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.64</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>227.5</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17987.67</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F2">Stock units credited under the Texas Instruments 2003 Director Compensation Plan, to be settled in common stock of the Issuer following the reporting person's termination of service as a director of the Issuer.  End-of-period holdings include stock units acquired pursuant to the dividend reinvestment provision of the Plan.</footnote>
        <footnote id="F3">Stock units credited under the Texas Instruments 2003 Director Compensation Plan, to be settled in common stock of the Issuer following the reporting person's termination of service as a director of the Issuer.</footnote>
        <footnote id="F1">Security converts to common stock on a one-for-one basis.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>CYNTHIA H. HAYNES, ATTORNEY IN FACT</signatureName>
        <signatureDate>2005-03-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
[{"type": "4", "sequence": "1", "filename": "doc.xml", "description": "PRIMARY DOCUMENT", "secsgml_size_bytes": 5162}]
X0202
4
2005-03-18
0000097476
TEXAS INSTRUMENTS INC
TXN
0001191525
CARP DANIEL A
12500 TI BOULEVARD
DALLAS
TX
75243
1
0
0
0
Common Stock
8664
D
Stock Units
1
2005-03-18
4
A
0
227.5
25.64
A
Common Stock
227.5
17987.67
D
Stock units credited under the Texas Instruments 2003 Director Compensation Plan, to be settled in common stock of the Issuer following the reporting person's termination of service as a director of the Issuer.  End-of-period holdings include stock units acquired pursuant to the dividend reinvestment provision of the Plan.
Stock units credited under the Texas Instruments 2003 Director Compensation Plan, to be settled in common stock of the Issuer following the reporting person's termination of service as a director of the Issuer.
Security converts to common stock on a one-for-one basis.
CYNTHIA H. HAYNES, ATTORNEY IN FACT
2005-03-21