File Nos. 333-174627

811-22564

AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 20, 2013

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. 14	x
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 16	x

GMO SERIES TRUST

(Exact Name of Registrant as Specified in Charter)

40 Rowes Wharf, Boston, Massachusetts 02110

(Address of principal executive offices)

617-330-7500

(Registrant’s telephone number, including area code)

with a copy to:

J.B. Kittredge, Esq. GMO Series Trust 40 Rowes Wharf Boston, Massachusetts 02110	Thomas R. Hiller, Esq. Ropes & Gray LLP Prudential Tower 800 Boylston Street Boston, Massachusetts 02199
(Name and address of agents for service)

It is proposed that this filing will become effective:

x Immediately upon filing pursuant to paragraph (b), or

¨ On                     , pursuant to paragraph (b), or

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

¨ 75 days after filing pursuant to paragraph (a)(2), of Rule 485.

This filing relates only to the 19 series of the Registrant listed on the front cover of the GMO Series Trust Prospectus, dated August 31, 2013, and filed with the Securities and Exchange Commission on August 30, 2013 with Post-Effective Amendment No. 13 under the Securities Act of 1933, as amended, and Amendment No. 15 under the Investment Company Act of 1940, as amended.

GMO SERIES TRUST

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 (the “1933 Act”) and the Investment Company Act of 1940 (the “1940 Act”), each as amended, the Registrant, GMO Series Trust, certifies that it meets all of the requirements for effectiveness of this Registration Statement under Rule 485(b) under the 1933 Act and has duly caused this Post-Effective Amendment No. 14 under the 1933 Act and Amendment No. 16 under the 1940 Act to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston and The Commonwealth of Massachusetts, on the 20th day of September, 2013.

GMO Series Trust
By:	J.B. KITTREDGE*
	J.B. Kittredge
Title:	President; Chief Executive Officer;
	Principal Executive Officer

Pursuant to the requirements of the 1933 Act, this Post-Effective Amendment No. 14 to GMO Series Trust’s Registration Statement under the 1933 Act has been signed below by the following persons in the capacities and on the date indicated.

Signatures	Title	Date
J.B. KITTREDGE* J.B. Kittredge	Trustee; President; Chief Executive Officer; Principal Executive Officer	September 20, 2013
SHEPPARD N. BURNETT* Sheppard N. Burnett	Treasurer; Chief Financial Officer; Principal Financial and Accounting Officer	September 20, 2013
MARIA D. FURMAN* Maria D. Furman	Trustee	September 20, 2013
SANDRA WHISTON* Sandra Whiston	Trustee	September 20, 2013

* By:	/s/ Jason Harrison
	Jason Harrison
	Attorney-in-Fact**

** Pursuant to Powers of Attorney for each of J.B. Kittredge and Sheppard N. Burnett, filed with the Securities and Exchange Commission (the “SEC”) as part of the Initial Registration Statement of the Registrant on May 31, 2011, pursuant to Power of Attorney for Maria D. Furman filed with the SEC as part of Pre-Effective Amendment No. 2 to the Registration Statement under the Securities Act and Amendment No. 2 to the Registration Statement under the 1940 Act on September 15, 2011, and pursuant to Power of Attorney for Sandra Whiston filed with the SEC as part of Post-Effective Amendment No. 5 to the Registration Statement under the Securities Act and Amendment No. 7 to the Registration Statement under the 1940 Act on December 21, 2011.

GMO SERIES TRUST ANNUAL UPDATE 485(b) XBRL FILING (SEPTEMBER 2013)

EXHIBIT INDEX

GMO SERIES TRUST

Exhibit Ref.	Title of Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX.101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX.101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase
Other.
1	Certificate of Clerk of the Trust certifying resolution by the Board of Trustees of the Trust required pursuant to Rule 483 under the Securities Act of 1933.