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                                                                     EXHIBIT 5.1

                       Opinion of Counsel

                    FOLEY, HOAG & ELIOT LLP
                     ONE POST OFFICE SQUARE
                BOSTON, MASSACHUSETTS 02109-2170


                    TELEPHONE 617-832-1000        1615 L STREET, N.W., SUITE 850
                          FACSIMILE                  WASHINGTON, D.C.  20036
                617-832-7000http://www.fhe.com         TEL: 202-775-0600
                                                       FAX: 202-857-0140



                              June 11, 1999

Progress Software Corporation
14 Oak Park
Bedford, MA 01730


Ladies and Gentlemen:

         We have acted as counsel for Progress Software Corporation, a
Massachusetts corporation (the "Company"), in connection with the preparation
and filing with the Securities and Exchange Commission under the Securities Act
of 1933, as amended, of a Registration Statement on Form S-8 (the "Registration
Statement") relating to the offering of up to 300,000 shares (the "Shares") of
the Company's common stock, $.01 par value ("Common Stock"), issuable, either
under awards currently issued and outstanding or under awards issuable
subsequent to the date hereof, pursuant to the Progress Software Corporation
1991 Employee Stock Purchase Plan (the "Plan").

         In arriving at the opinions expressed below, we have examined and
relied on the following documents:

         (i)      the Registration Statement;

         (ii)     the Plan;

         (iii)    the Restated Articles of Organization of the Company, as
                  amended as of the date hereof;

         (iv)     the By-Laws of the Company, as amended as of the date hereof;
                  and

         (v)      the records of meetings and consents of the Board of Directors
                  and stockholders of the Company provided to us by the Company.


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In addition, we have examined and relied on the originals or copies certified or
otherwise identified to our satisfaction of all such other records, documents
and instruments of the Company and such other persons, and we have made such
investigations of law, as we have deemed appropriate as a basis for the opinions
expressed below. We have assumed the genuineness of all signatures and the
authenticity of all documents submitted to us as originals and the conformity to
the original documents of all documents submitted to us as certified or
photostatic copies.

         We express no opinion other than as to the laws of The Commonwealth of
Massachusetts.

         Based upon the foregoing, we are of the opinion that the Company has
the corporate power necessary for the issuance of the Shares under the Plan, as
contemplated by the Registration Statement. The Shares have been duly authorized
and, when issued against payment of the agreed consideration therefor in
accordance with the respective exercise prices therefor as described in the
awards relating thereto and the Plan, will be validly issued, fully paid and
non-assessable.

         We consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement.

                                       Very truly yours,

                                       FOLEY, HOAG & ELIOT LLP



                                       By /s/ Robert W. Sweet, Jr.
                                          ------------------------------------
                                          A Partner