As filed with the Securities and Exchange Commission on November 13, 2012

Registration No. 33-35576

811-06128

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 25	x

and

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 26	x
(Check appropriate box or boxes)

PUTNAM MULTI-CAP GROWTH FUND

(Exact name of registrant as specified in charter)

One Post Office Square,

Boston, Massachusetts 02109

(Address of principal executive offices)

(617) 292-1000

Registrant’s Telephone Number, including Area Code

It is proposed that this filing will become effective (check appropriate box)

¨ immediately upon filing pursuant to paragraph (b)

x on November 13, 2012 pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a) (1)

¨ on (date) pursuant to paragraph (a) (1)

¨ 75 days after filing pursuant to paragraph (a) (2)

¨ on (date) pursuant to paragraph (a) (2) of Rule 485.

If appropriate, check the following box:

¨ this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Copy to:

Robert T. Burns, Vice President PUTNAM MULTI-CAP GROWTH FUND One Post Office Square Boston, Massachusetts 02109	JOHN W. GERSTMAYR, Esquire ROPES & GRAY LLP Prudential Tower 800 Boylston Street Boston, Massachusetts 02199-3600
(Name and address of agent for service)

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Amendment to its Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Boston, and The Commonwealth of Massachusetts, on the 13th day of November, 2012.

Putnam Multi-Cap Growth Fund

By: /s/ Jonathan S. Horwitz, Executive Vice President, Principal Executive Officer and Compliance Liaison

Pursuant to the requirements of the Securities Act of 1933, this Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

Signature	Title
Jameson A. Baxter*	Chair, Board of Trustees and Trustee
Robert L. Reynolds*	President and Trustee
Jonathan S. Horwitz*	Executive Vice President, Principal Executive Officer and Compliance Liaison
Steven D. Krichmar*	Vice President and Principal Financial Officer
Janet C. Smith*	Vice President, Assistant Treasurer and Principal Accounting Officer
Liaquat Ahamed*	Trustee
Ravi Akhoury*	Trustee
Barbara M. Baumann*	Trustee
Charles B. Curtis*	Trustee
Robert J. Darretta*	Trustee
Katinka Domotorffy*	Trustee

John A. Hill*	Trustee
Paul L. Joskow*	Trustee
Elizabeth T. Kennan*	Trustee
Kenneth R. Leibler*	Trustee
Robert E. Patterson*	Trustee
George Putnam, III*	Trustee
W. Thomas Stephens*	Trustee

By: /s/ Jonathan S. Horwitz, as Attorney-in-Fact

November 13, 2012

* Signed pursuant to power of attorney filed in Post-Effective Amendment No. 24 to the Registrant’s Registration Statement filed on October 26, 2012.