    <SEC-DOCUMENT>0001193125-21-087005-index.html : 20210319
    <SEC-HEADER>0001193125-21-087005.hdr.sgml : 20210319
    <ACCEPTANCE-DATETIME>20210319104904
    ACCESSION NUMBER:		0001193125-21-087005
    CONFORMED SUBMISSION TYPE:	DEF 14A
    PUBLIC DOCUMENT COUNT:		14
    CONFORMED PERIOD OF REPORT:	20210511
    FILED AS OF DATE:		20210319
    DATE AS OF CHANGE:		20210319

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			Arthur J. Gallagher & Co.
    		CENTRAL INDEX KEY:			0000354190
    		STANDARD INDUSTRIAL CLASSIFICATION:	INSURANCE AGENTS BROKERS & SERVICES [6411]
    		IRS NUMBER:				362151613
    		STATE OF INCORPORATION:			IL
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEF 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-09761
    		FILM NUMBER:		21756884

    	BUSINESS ADDRESS:
    		STREET 1:		2850 GOLF ROAD
    		CITY:			ROLLING MEADOWS
    		STATE:			IL
    		ZIP:			60008-4050
    		BUSINESS PHONE:		630-773-3800

    	MAIL ADDRESS:
    		STREET 1:		2850 GOLF ROAD
    		CITY:			ROLLING MEADOWS
    		STATE:			IL
    		ZIP:			60008-4050

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ARTHUR J. GALLAGHER & CO.
    		DATE OF NAME CHANGE:	20190819

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	GALLAGHER ARTHUR J & CO
    		DATE OF NAME CHANGE:	19920703
    </SEC-HEADER>
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    <SEQUENCE>1
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    <DESCRIPTION>DEF 14A
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    Document 1 - file: d92526ddef14a.htm

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    <SEQUENCE>2
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    <DESCRIPTION>GRAPHIC
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    <DESCRIPTION>GRAPHIC
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    <DESCRIPTION>GRAPHIC
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    <DESCRIPTION>GRAPHIC
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    Document 13 - file: g92526pc_1.jpg

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