Exhibit 5.1

                         [Andrea D. Kantor Letterhead]

                                                        June 24, 2005

GSE Systems, Inc.
9189 Red Branch Road
Columbia, MD  21045

Gentlemen:

     Reference  is  made  to  the  Registration  Statement  on  Form  S-3 of GSE
Systems, Inc. (the "Company") relating  to  the registration of shares of Common
Stock, par value $.01 per share (the "Common Stock"), of the Company.

     I am General  Counsel of the  Company,  and have  examined  such  corporate
records and other documents as I have deemed  relevant.  Based upon the above, I
am of the  opinion  that the shares of Common  Stock to be sold  pursuant to the
Registration  Statement have been authorized and, when issued upon conversion of
the  note  held by the  selling  stockholder  or when  issued  and  paid  for in
accordance with the warrant held by the selling  stockholder,  each as described
in  the  Registration  Statement,  will  be  validly  issued,  fully  paid,  and
non-assessable.

     I hereby  consent  to the  filing  of this  opinion  as an  exhibit  to the
Registration  Statement and the use of my name in the Prospectus included in the
Registration Statement.

                                        Very truly yours,


                                        Andrea D. Kantor