As filed with the Securities and Exchange
Commission on October 12, 2012

1933 Act File No. 33-12947
1940 Act File No. 811-05079

U.S. SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 þ
PRE-EFFECTIVE AMENDMENT NO. o
POST-EFFECTIVE AMENDMENT NO. 38

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 þ
AMENDMENT NO. 39
(CHECK APPROPRIATE BOX OR BOXES)

JOHN HANCOCK TAX-EXEMPT SERIES FUND

(EXACT NAME OF REGISTRANT AS SPECIFIED IN CHARTER)

601 CONGRESS STREET
BOSTON, MASSACHUSETTS 02210-2805
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES) (ZIP CODE)

REGISTRANT’S TELEPHONE NUMBER, INCLUDING AREA CODE
(617) 663-2999

THOMAS M. KINZLER, ESQ.
601 CONGRESS STREET
BOSTON, MASSACHUSETTS 02210-2805
(NAME AND ADDRESS OF AGENT FOR SERVICE)

COPIES OF COMMUNICATIONS TO:

MARK P. GOSHKO, ESQ.
K & L GATES LLP
ONE LINCOLN STREET
BOSTON, MA 02111-2950

APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING: As soon as practicable after the effective date of this Registration Statement.

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

þ immediately upon filing pursuant to paragraph (b) of Rule 485
o on (date) pursuant to paragraph (b) of Rule 485
o 60 days after filing pursuant to paragraph (a)(1) of Rule 485
o on (date) pursuant to paragraph (a)(1) of Rule 485
o 75 days after filing pursuant to paragraph (a)(2) of Rule 485
o on (date) pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

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

TABLE OF CONTENTS

EX-101 INSTANCE DOCUMENT

EX-101 SCHEMA DOCUMENT

EX-101 CALCULATION LINKBASE DOCUMENT

EX-101 LABELS LINKBASE DOCUMENT

EX-101 PRESENTATION LINKBASE DOCUMENT

EX-101 DEFINITION LINKBASE DOCUMENT

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 Amendment to the Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Amendment to the 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 12th day of October, 2012.

JOHN HANCOCK TAX-EXEMPT SERIES FUND
By:	/s/ Hugh McHaffie Hugh McHaffie
	President

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 date indicated.

Signature	Title	Date
/s/ Hugh McHaffie Hugh McHaffie	Trustee	October 12, 2012
/s/ Charles A. Rizzo Charles A. Rizzo	Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)	October 12, 2012
/s/ William H. Cunningham* William H. Cunningham	Trustee	October 12, 2012
/s/ Deborah C. Jackson* Deborah C. Jackson	Trustee	October 12, 2012
/s/ John A. Moore* John A. Moore	Trustee	October 12, 2012
/s/ Steven R. Pruchansky* Steven R. Pruchansky	Trustee	October 12, 2012
/s/ Gregory A. Russo* Gregory A. Russo	Trustee	October 12, 2012
/s/ John G. Vrysen* John G. Vrysen	Trustee	October 12, 2012
*By: Power of Attorney

By:	/s/ Nicholas J. Kolokithas Nicholas J. Kolokithas	October 12, 2012
	Attorney-in-Fact

* Pursuant to Power of Attorney filed with Post-Effective Amendment No. 37 to the Trust’s Registration Statement on September 26, 2012

Exhibit Index

EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase Document
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase Document

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