UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    Form 13F
                               Form 13F COVER PAGE
Report for the Calendar Year or Quarter Ended: 12/31/2011
Check here if Amendment []; Amendment Number:
                                               -------
This Amendment (Check only one.):               [] is a restatement.
                                                [] adds new holdings entries.

Institutional Investment Manager Filing this Report:


Name:      Harleysville Group Inc.

Address:   355 Maple Avenue
           Harleysville, PA 19438-2297


Form 13F File Number: 28- 4718


The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained herein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this submission.

Persons Signing this Report on Behalf of Reporting Manager:

Name:   Mark R. Cummins
Title:  Executive Vice President & Treasurer
Phone:  215-256-5025

Signature,  Place,  and  Date  of  Signing:

/s/ Mark R. Cummins                Harleysville, PA                   2/13/2012
---------------------------------  ---------------------------------  ----------
[Signature]                        [City, State]                      [Date]



Report  Type  (Check  only  one):

[X]     13F HOLDINGS REPORT. (Check here if all holdings of this reporting
        manager are reported in this report.)

[ ]     13F NOTICE. (Check here if no holdings reported are in this report,
        and all holdings are reported by other reporting manager(s).)

[ ]     13F COMBINATION REPORT. (Check here if a portion of the holdings for
        this reporting manager are reported in this report and a portion are
        reported by other reporting manager(s).)

List of Other Managers Reporting for this Manager:




                              Form 13F SUMMARY PAGE

Report Summary:

Number of Other Included Managers:                    0

Form 13F Information Table Entry Total:               3

Form 13F Information Table Value Total:  $      115,913
                                         --------------
                                         (In Thousands)


List of Other Included Managers:

Provide a numbered list of the name(s) and 13F file number(s) of all
institutional investment managers with respect to which this report is filed,
other than the manager filing this report.
NONE







                                                  FORM 13F INFORMATION TABLE

              COLUMN 1                  COLUMN 2    COLUMN 3  COLUMN 4      COLUMN 5       COLUMN 6  COLUMN 7      COLUMN 8
------------------------------------ -------------- --------- -------- ------------------ ---------- -------- ------------------
                                                               VALUE    SHRS OR  SH/ PUT/ INVESTMENT  OTHER    VOTING AUTHORITY
           NAME OF ISSUER            TITLE OF CLASS   CUSIP   (x$1000)  PRN AMT  PRN CALL DISCRETION MANAGERS  SOLE  SHARED NONE
------------------------------------ -------------- --------- -------- --------- --- ---- ---------- -------- ------ ------ ----
                                                                                           
HARLEYSVILLE SAVINGS FINL CO         COM            412865107    1,774   123,748 SH       SOLE       N/A       1,774      0    0
VANGUARD INSTL TOTAL STOCK MKT INDX  EQUITY MUT FD  922040407   91,829 3,242,549 SH       SOLE       N/A      91,829      0    0
VANGUARD FTSE ALL WORLD EX U.S. FUND EQUITY MUT FD  922042783   22,310   287,015 SH       SOLE       N/A      22,310      0    0