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                                                                  EXECUTION COPY

                                                                   Exhibit 10.20

                                 THIRD AMENDMENT
                        TO REGISTRATION RIGHTS AGREEMENT

     This THIRD AMENDMENT TO REGISTRATION RIGHTS AGREEMENT (the "Third
Amendment"), is entered into this 9th day of September, 2003, by and among Nobel
Learning Communities, Inc., formerly Nobel Education Dynamics, Inc., a Delaware
corporation (the "Company") and the individuals and/or entities that are parties
to the Original Agreement (as defined below).

                               B A C K G R O U N D

     WHEREAS, the Company and certain other individuals and/or entities are
parties to a Registration Rights Agreement, dated as of August 19, 1994, as
amended on February 23, 1996, and as further amended on June 17, 2003 (the
"Original Agreement");

     WHEREAS, on the date hereof, the Company and certain investors entered into
a Series F Convertible Preferred Stock Purchase Agreement (the "Series F
Purchase Agreement"); and

     WHEREAS, in connection with the execution of the Series F Purchase
Agreement, the Company and the parties to the Original Agreement desire to amend
the Original Agreement as set forth herein.

     NOW, THEREFORE, in order to implement the foregoing and in consideration of
the mutual agreements contained herein and the Original Agreement, and for other
good and valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the Company and the other parties hereto, intending to be legally
bound hereby, agree as follows:

     1. Section 4(c). Section 4(c) of the Original Agreement is hereby amended
and restated in its entirety to read as follows:

     "(c) The Company may not include in any registration statement referred to
     in this Section 4 any shares of Common Stock to be sold for the account of
     any person not entitled as of September 9, 2003 to registration rights with
     respect to such shares. The Company may include in any registration
     requested pursuant to this Section 4 hereof any shares of Common Stock for
     sale for its own account or for the account of any other person entitled to
     "piggy-back" or "incidental rights" as of September 9, 2003, provided that
     such inclusion shall not affect the number of shares of Restricted Stock
     that can be sold in the related offering. In connection with an
     underwritten offering, if the managing underwriter advises the Company in
     writing that in its opinion the number of shares of Restricted Stock
     requested by the holders of Restricted Stock to be registered exceeds the
     number which can be sold in such offering, the Company shall include in
     such registration statement the number of shares of Restricted Stock that,
     in the opinion of the managing underwriter, can be sold as follows: (i)
     first, the Restricted Stock requested to be registered, pro rata among the
     holders of Restricted Stock that have requested their Restricted Stock to
     be registered, (ii) second, Common Stock requested to be registered by
     holders of existing registration rights as of September 9, 2003 and (iii)
     third, any other

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                                                                  EXECUTION COPY

         Common Stock requested to be included in such registration. Except for
         registration statements on Form S-4, S-8 or any successor thereto,
         registration statements registering securities to be issued by the
         Company to the seller or sellers in connection with an acquisition by
         the Company and registration statements required to be filed for
         holders of Common Stock who, as of September 9, 2003, are entitled to
         "demand" registration rights, the Company will not file with the
         Commission any other registration statement with respect to its Common
         Stock, whether for its own account or that of other stockholders, from
         the date of receipt of a notice from requesting holders pursuant to
         this Section 4 until the completion of the period of distribution of
         the registration contemplated thereby."

         2. Section 5. The last sentence of Section 5 of the Original Agreement
is hereby amended and restated in its entirety to read as follows:

         "Notwithstanding the provisions of this Section 5, if the registration
         was initiated by the Company at the request of a person or persons
         entitled to demand rights as of September 9, 2003, exercising such
         demand rights, priority in underwriter cutbacks with respect to such
         registration shall be governed by the provisions of their particular
         agreement providing for such demand rights, provided that the holders
         of Restricted Stock that have requested inclusion of their Restricted
         Stock to be included therein shall have priority over any other persons
         holding securities requested to be included in such registration."

         3. Sections 5 and 6. In Sections 5 and 6, all references to "June 17,
2003" are deleted and replaced with "September 9, 2003."

         4. Effect of Third Amendment. In all other respects, the Original
Agreement, as amended hereby, remains in full force and effect as written.

         5. Counterparts. This Third Amendment may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. This document may also be
delivered by facsimile transmission with the same force and effect as if
originally executed copies of this document were delivered to all parties.

         6. Governing Law. This Third Amendment shall be governed by and
construed in accordance with the laws of the State of Delaware.

                         [SIGNATURES ON FOLLOWING PAGE]


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                                                                  EXECUTION COPY

     IN WITNESS WHEREOF, the parties hereto have duly executed this Third
Amendment to Registration Rights Agreement as of the date first written above.

                                           NOBEL LEARNING COMMUNITIES, INC.

                                           By: /s/ George H. Bernstein
                                               ---------------------------------
                                           Name:  George H. Bernstein
                                           Title: Chief Executive Officer

                                           By: /s/ D. Scott Clegg
                                               ---------------------------------
                                           Name:  D. Scott Clegg
                                           Title: Vice Chairman, President and
                                                  Chief Operating Officer

                                           EDISON VENTURE FUND II, L.P.

                                           By: Edison Partners II, its general
                                               partner


                                               By: /s/ John H. Martinson
                                                   -----------------------------
                                               Name: John Martinson
                                               Title: General Partner