Item 1(a).

Name of Issuer:

Acuity Brands, Inc.

Item 1(b).

Address of Issuer’s Principal Executive Offices:

1170 Peachtree Street Northeast

Suite 2300

Atlanta, GA 30309-7676

Item 2(a).

Name of Persons Filing:

Generation Investment Management LLP;

Generation Investment Management US LLP;

Generation IM Fund plc; and

Generation IM Global Equity Fund LLC.

Item 2(b).

Address of Principal Business Office or, if none, Residence:

Generation Investment Management LLP: 20 Air Street, 7^th floor, London, United Kingdom W1B 5AN.

Generation Investment Management US LLP: One Bryant Park, 48th Floor, New York, NY 10036.

Generation IM Fund plc: Georges Court, 54-62 Townsend Street, Dublin 2, Ireland

Generation IM Global Equity Fund LLC: c/o One Bryant Park, 48th Floor, New York, NY 10036.

Item 2(c).

Citizenship:

Generation Investment Management LLP – England and Wales

Generation Investment Management US LLP - Delaware

Generation IM Fund plc - Ireland

Generation IM Global Equity Fund LLC - Delaware

Item 2(d).

Title of Class of Securities:

Common Stock

Item 2(e).

CUSIP Number:

00508Y102

Item 3.

If this statement is filed pursuant to Rules 13d-1(b) or 13d-2(b) or (c), check whether the person filing is a:

(a)

[  ]

Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o).

(b)

[  ]

Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).

(c)

[  ]

Insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C. 78c).

(d)

[  ]

Investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

(e)

[  ]

An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

(f)

[  ]

An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

(g)

[  ]

A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);

(g)

[  ]

A savings association as defined in Section 3of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

[  ]

A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

[  ]

A non- U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);

(k)

[  ]

A group, provided that all the members are persons specified with Rule 13d-1(b)(1)(ii)(A) through (J).

Item 4.

Ownership.

(a).

Amount beneficially owned:

See the response(s) to Item 9 on the attached cover pages.

(b).

Percent of Class:

See the response(s) to Item 11 on the attached cover pages.

(c).

Number of shares as to which such person has:

(i).

Sole power to vote or to direct the vote:  See the response(s) to Item 5 on the attached cover pages.

(ii).

Shared power to vote or to direct the vote:  See the response(s) to Item 6 on the attached cover pages.

(iii).

Sole power to dispose or to direct the disposition of:  See the response(s) to Item 7 on the attached cover pages.

(iv).

Shared power to dispose or to direct the disposition of:  See the response(s) to Item 8 on the attached cover pages.

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 5 percent of the class of securities, check the following:

Not applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company.

Not applicable.

Item 8.

Identification and Classification of Members of the Group.

Not applicable.

Item 9.

Notice of Dissolution of Group.

Not applicable.

Item 10.

Certification.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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.