<SEC-DOCUMENT>0000049826-16-000175.txt : 20160217
<SEC-HEADER>0000049826-16-000175.hdr.sgml : 20160217
<ACCEPTANCE-DATETIME>20160217165508
ACCESSION NUMBER:		0000049826-16-000175
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20160212
FILED AS OF DATE:		20160217
DATE AS OF CHANGE:		20160217

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ILLINOIS TOOL WORKS INC
		CENTRAL INDEX KEY:			0000049826
		STANDARD INDUSTRIAL CLASSIFICATION:	GENERAL INDUSTRIAL MACHINERY & EQUIPMENT [3560]
		IRS NUMBER:				361258310
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		155 HARLEM AVENUE
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60025
		BUSINESS PHONE:		8477247500

	MAIL ADDRESS:	
		STREET 1:		155 HARLEM AVENUE
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60025

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHEUNEMAN RANDALL J
		CENTRAL INDEX KEY:			0001470159

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-04797
		FILM NUMBER:		161434031

	MAIL ADDRESS:	
		STREET 1:		155 HARLEM AVE.
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60025
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_145574609715121.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
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    <schemaVersion>X0306</schemaVersion>

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    <periodOfReport>2016-02-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000049826</issuerCik>
        <issuerName>ILLINOIS TOOL WORKS INC</issuerName>
        <issuerTradingSymbol>ITW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001470159</rptOwnerCik>
            <rptOwnerName>SCHEUNEMAN RANDALL J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ILLINOIS TOOL WORKS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>155 HARLEM AVENUE</rptOwnerStreet2>
            <rptOwnerCity>GLENVIEW</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP &amp; Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-02-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1502</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4656</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        <nonDerivativeTransaction>
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                <value>Common Stock</value>
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            <transactionDate>
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        </nonDerivativeTransaction>
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    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
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            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2016-02-13</value>
                <footnoteId id="F2"/>
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            <expirationDate>
                <value>2025-02-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5425.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Unit (granted 02/13/15)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
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            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            <ownershipNature>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>55.71</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2013-02-10</value>
            </exerciseDate>
            <expirationDate>
                <value>2022-02-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>11977.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11977</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>43.64</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-02-12</value>
            </exerciseDate>
            <expirationDate>
                <value>2020-02-12</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15641.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15641</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>78.59</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2015-02-14</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-02-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6820.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6820</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
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                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeHolding>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit (granted 2/15/2013)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-02-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1502</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
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            <exerciseDate>
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            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1502.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
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            <ownershipNature>
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        </derivativeTransaction>
        <derivativeHolding>
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                <value>Restricted Stock Unit (granted 02/14/2014)</value>
                <footnoteId id="F1"/>
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            <conversionOrExercisePrice>
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                <underlyingSecurityTitle>
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                <underlyingSecurityShares>
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            <postTransactionAmounts>
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            <conversionOrExercisePrice>
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            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2014-02-15</value>
                <footnoteId id="F2"/>
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            <expirationDate>
                <value>2023-02-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9664.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9664</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
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        </derivativeHolding>
        <derivativeHolding>
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            <conversionOrExercisePrice>
                <value>55.81</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2012-02-11</value>
            </exerciseDate>
            <expirationDate>
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            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
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                <underlyingSecurityShares>
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        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option</value>
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            <conversionOrExercisePrice>
                <value>91.88</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-02-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>5827</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2017-02-12</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2026-02-12</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5827.0</value>
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                <directOrIndirectOwnership>
                    <value>D</value>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit (granted 2/12/2016)</value>
                <footnoteId id="F1"/>
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            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-02-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionShares>
                    <value>1269</value>
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                <transactionPricePerShare>
                    <value>0</value>
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                    <value>A</value>
                </transactionAcquiredDisposedCode>
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            <expirationDate>
                <footnoteId id="F3"/>
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                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>1269.0</value>
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                    <value>1269</value>
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                    <value>D</value>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit (RSU) represents a contingent right to receive one share of the Company's common stock.</footnote>
        <footnote id="F2">Options vest in four (4) equal annual installments beginning one year from date of grant.</footnote>
        <footnote id="F3">Each RSU vests 100% three years from the date of grant.</footnote>
        <footnote id="F4">The RSU award became vested and payable on February 15, 2016.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Randall J. Scheuneman by Janet O. Love, Deputy General Counsel &amp; Assistant Secretary, Attorney-In-Fact POA on File</signatureName>
        <signatureDate>2016-02-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>ex-24.htm
<DESCRIPTION>POWER OF ATTORNEY- SCHEUNEMAN
<TEXT>
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<pre>
POWER OF ATTORNEY

The undersigned hereby constitutes and appoints each of E. Scott Santi,  Michael M. Larsen, and Janet O. Love signing singly, his true and lawful attorney-in-fact to:

(1)    execute for and on behalf of the undersigned Forms 3, 4 and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the rules thereunder;

(2)    do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such Form 3, 4 or 5 and the timely filing of such form with the United States Securities and Exchange Commission ("SEC") and any other person; and

(3)    take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion.

The undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, are not assuming any of the undersigned's responsibilities to comply with Section 16 of the Exchange Act.

This Power of Attorney shall be effective on the date set forth below and shall continue in full force and effect until the date on which the undersigned shall cease to be subject to Section 16 of the Exchange Act and the rules thereunder or until such earlier date on which written notification executed by the undersigned is filed with the SEC expressly revoking this Power of Attorney.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 22nd day of October 2015.


/s/ Randall J. Scheuneman
Randall J. Scheuneman

Signed and sworn to before me on
this 22nd day of October 2015.

/s/ Meghan P. Callero
Notary Public
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
