UNITED STATES
                  SECURITIES AND EXCHANGE COMMISSION
                        Washington, D.C. 20549


                             SCHEDULE 13G

               Under the Securities Exchange Act of 1934


                           (Amendment No. )*


                         Arthur J. Gallagher & Co
                             (Name of Issuer)

                               Common Stock
                      (Title of Class of Securities)

                                363576109
                              (CUSIP Number)

                            December 31, 2013
         (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information
which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of
that section of the Act but shall be subject to all other provisions of
the Act (however, see the Notes).

















CUSIP: 363576109                                                Page 1 of 8


 1   NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
     Capital Group International, Inc.


 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
     INSTRUCTIONS)                                                 (a)

                                                                    (b)
 3   SEC USE ONLY


 4   CITIZENSHIP OR PLACE OF ORGANIZATION

     California

             5   SOLE VOTING POWER

                  7,670,521


             6   SHARED VOTING POWER
 NUMBER OF
   SHARES         NONE
BENEFICIALL
 Y OWNED BY
             7   SOLE DISPOSITIVE POWER
    EACH
 REPORTING        7,676,221
   PERSON
   WITH:
             8   SHARED DISPOSITIVE POWER

                  NONE

 9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     7,676,221          Beneficial ownership disclaimed pursuant to Rule
     13d-4


 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
     (SEE INSTRUCTIONS)


 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     5.8%

 12  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

     HC










CUSIP: 363576109                                                Page 2 of 8




 1   NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
     Capital International Investors


 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
     INSTRUCTIONS)                                                 (a)

                                                                    (b)
 3   SEC USE ONLY


 4   CITIZENSHIP OR PLACE OF ORGANIZATION



             5   SOLE VOTING POWER

                  7,277,537


             6   SHARED VOTING POWER
 NUMBER OF
   SHARES         NONE
BENEFICIALL
 Y OWNED BY
             7   SOLE DISPOSITIVE POWER
    EACH
 REPORTING        7,277,537
   PERSON
   WITH:
             8   SHARED DISPOSITIVE POWER

                  NONE

 9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     7,277,537          Beneficial ownership disclaimed pursuant to Rule
     13d-4


 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
     (SEE INSTRUCTIONS)


 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     5.5%

 12  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

     IA







CUSIP: 363576109                                                Page 3 of 8



                  SECURITIES AND EXCHANGE COMMISSION
                         Washington, DC 20549

                             Schedule 13G
               Under the Securities Exchange Act of 1934


Amendment No.

Item 1(a)     Name of Issuer:
       Arthur J. Gallagher & Co

Item 1(b)     Address of Issuer's Principal Executive Offices:
       Two Pierce Place
       Itasca, IL 60143-3141

Item 2(a)     Name of Person(s) Filing:
       Capital Group International, Inc. and Capital International
       Investors

Item 2(b)     Address of Principal Business Office or, if none,
       Residence:
       11100 Santa Monica Blvd.
       Los Angeles, CA 90025

Item 2(c)     Citizenship:   N/A

Item 2(d)     Title of Class of Securities:
       Common Stock

Item 2(e)     CUSIP Number:
       363576109

Item 3     If this statement is filed pursuant to sections 240.13d-1(b)
       or 240.13d-2(b) or (c), check whether the person filing is a:
       (e)      [X]     An investment adviser in accordance with
            section 240.13d-1(b)(1)(ii)(E).
       (g)     [X]     A parent holding company or control person in
            accordance with section 240.13d-1(b)(1)(ii)(G).

Item 4     Ownership

       Provide the following information regarding the aggregate
       number and percentage of the class of securities of the issuer
       identified in Item 1.


       (a)    Amount beneficially owned:
       (b)    Percent of class:
       (c)    Number of shares as to which the person has:
       (i)    Sole power to vote or to direct the vote:
       (ii)   Shared power to vote or to direct the vote:
       (iii)  Sole power to dispose or to direct the disposition of:
       (iv)   Shared power to dispose or to direct the disposition of:

       See pages 2 and 3

       Capital Group International, Inc. ("CGII") is the parent
       holding company of a group of investment management companies
CUSIP: 363576109                                                Page 4 of 8




       that hold investment power and, in some cases, voting power
       over the securities reported in this Schedule 13G.  The
       investment management companies, which include a "bank" as
       defined in Section 3(a)(6) of the Securities Exchange Act of
       1934 (the "Act") and several investment advisers registered
       under Section 203 of the Investment Advisers Act of 1940,
       provide investment advisory and management services for their
       respective clients which include registered investment
       companies and institutional accounts.  CGII does not have
       investment power or voting power over any of the securities
       reported herein.  However, by virtue of Rule 13d-3 under the
       Act, CGII may be deemed to "beneficially own" 7,676,221 shares
       or 5.8% of the 131,538,000 shares believed to be outstanding.

       Capital International Investors is deemed to be the beneficial
       owner of 7,277,537 shares or 5.5% of the 131,538,000 shares
       believed to be outstanding as a result of Capital Research and
       Management Company acting as investment adviser to various
       investment companies registered under Section 8 of the
       Investment Company Act of 1940.

       CGII, its investment management subsidiaries and Capital
       International Investors division of Capital Research and
       Management Company collectively provide investment management
       services under the name "Capital International Investors."



Item 5     Ownership of Five Percent or Less of a Class.  If this
       statement is being filed to report the fact that as of the date
       hereof the reporting person has ceased to be the beneficial
       owner of more than five percent of the class of securities,
       check the following: [ ]

Item 6     Ownership of More than Five Percent on Behalf of Another
       Person: N/A

Item 7     Identification and Classification of the Subsidiary Which
       Acquired the Security Being Reported on By the Parent Holding
       Company or Control Person.

       1. Capital International Investors ("CII") is a division of
          Capital Research and Management Company.  Capital Research
          and Management Company is an investment adviser registered
          under Section 203 of the Investment Advisers Act of 1940.
       2. Capital Guardian Trust Company ("CGTC") is a bank as defined
          in Section 3(a)(6) of the Act and an investment adviser
          registered under Section 203 of the Investment Adviser Act of
          1940, and a wholly owned subsidiary of Capital Group
          International, Inc.
       3. Capital International Limited ("CIL") does not fall within
          any of the categories described in Rule 13d-1(b)(ii)(A-F) but
          its holdings of any reported securities come within the five
          percent limitation as set forth in a December 15, 1986 no-
          action letter from the Staff of the Securities and Exchange
          Commission to The Capital Group Companies, Inc. CIL is a
          wholly owned subsidiary of Capital Group International, Inc.


CUSIP: 363576109                                                Page 5 of 8



       4. Capital International Sarl ("CISA") does not fall within any
          of the categories described in Rule 13d-1(b)(ii)(A-F) but its
          holdings of any reported securities come within the five
          percent limitation as set forth in a December 15, 1986 no-
          action letter from the Staff of the Securities and Exchange
          Commission to The Capital Group Companies, Inc. CISA is a
          wholly owned subsidiary of Capital Group International, Inc.

Item 8     Identification and Classification of Members of the Group:
       N/A

Item 9     Notice of Dissolution of Group:  N/A

Item 10     Certification

       By signing below, I certify that, to the best of my knowledge
       and belief, the securities referred to above were acquired and
       are held in the ordinary course of business and were not
       acquired and are not held for the purpose of or with the effect
       of changing or influencing the control of the issuer of the
       securities and were not acquired and are not held in connection
       with or as a participant in any transaction having that purpose
       or effect.

     Signature

       After reasonable inquiry and to the best of my knowledge and
       belief, I certify that the information set forth in this
       statement is true, complete and correct.

        Date:          February 10, 2014

        Signature:     ***Peter C. Kelly
        Name/Title:    Peter C. Kelly, Secretary
                       Capital Group International, Inc.

        Date:          February 10, 2014

        Signature:     **Robert W. Lovelace
        Name/Title:    Robert W. Lovelace, Senior Vice President
                       Capital International Investors




        ***By  /s/ Liliane Corzo
               Liliane Corzo
               Attorney-in-fact

          Signed pursuant to a Power of Attorney dated January 9, 2014
          included as an Exhibit to Schedule 13G filed with the
          Securities and Exchange Commission by Capital Group
          International, Inc. on February 7, 2014 with respect to
          Seattle Genetics Incorporated.


CUSIP: 363576109                                                Page 6 of 8






























































CUSIP: 363576109                                                Page 7 of 8


                               AGREEMENT

                            Los Angeles, CA


   Capital Group International, Inc. ("CGII") and Capital
International Investors ("CII") hereby agree to file a joint statement
on Schedule 13G under the Securities Exchange Act of 1934 (the "Act")
in connection with their beneficial ownership of Common Stock issued by
Arthur J. Gallagher & Co.

   CGII and CII state that they are each entitled to individually use
Schedule 13G pursuant to Rule 13d-1(c) of the Act.

   CGII and CII are each responsible for the timely filing of the
statement and any amendments thereto, and for the completeness and
accuracy of the information concerning each of them contained therein
but are not responsible for the completeness or accuracy of the
information concerning the others.

                 CAPITAL GROUP INTERNATIONAL, INC.

                 BY:              ***Peter C. Kelly
                                  Peter C. Kelly, Secretary
                                   Capital Group International,
                                   Inc.


                 CAPITAL INTERNATIONAL INVESTORS

                 BY:              **Robert W. Lovelace
                                  Robert W. Lovelace, Senior Vice
                                   President
                                   Capital International Investors


***B /s/ Liliane Corzo
y
     Liliane Corzo
     Attorney-in-fact

     Signed pursuant to a Power of Attorney dated January 9, 2014
     included as an Exhibit to Schedule 13G filed with the Securities
     and Exchange Commission by Capital Group International, Inc. on
     February 7, 2014 with respect to Seattle Genetics Incorporated
















CUSIP: 363576109                                                Page 8 of 8