UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934 (Amendment No.    )

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¨  Definitive Proxy Statement

þ  Definitive Additional Materials

¨  Soliciting Material Pursuant to §240.14a-12

ACUITY BRANDS, INC.

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 (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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