    <SEC-DOCUMENT>0001193125-22-081816-index.html : 20220323
    <SEC-HEADER>0001193125-22-081816.hdr.sgml : 20220323
    <ACCEPTANCE-DATETIME>20220322184605
    ACCESSION NUMBER:		0001193125-22-081816
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		3
    FILED AS OF DATE:		20220323
    DATE AS OF CHANGE:		20220322

    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:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-09761
    		FILM NUMBER:		22761100

    	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>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>d245239ddefa14a.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: d245239ddefa14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>g245239g19r10.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: g245239g19r10.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>g245239g19r11.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: g245239g19r11.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>