EXHIBIT 21.1 GSE SYSTEMS, INC. FORM 10-K For the Year Ended December 31, 1998 SUBSIDIARIES OF REGISTRANT The companies listed below are directly or indirectly owned 100% by GSE Systems, Inc. and are included in its consolidated financial statements. GS Information Systems FSC Ltd, GSE Systems International Ltd, MSHI, Inc., GSE Power Systems AB and GSE Process Solutions, Inc. are wholly owned subsidiaries of GSE Systems, Inc. GP International Engineering & Simulation, Inc. and GSE Services Company L.L.C. are wholly owned subsidiaries of GSE Power Systems, Inc. which is a wholly owned subsidiary of MSHI, Inc. GSE Process Solutions B.V. is a wholly owned subsidiary of GSE Process Solutions, Inc. GSE Process Solutions Belgium N.V. and GSE Process Solutions Singapore (Pte) Limited are wholly owned subsidiaries of GSE Process Solutions B.V. J. L. Ryan, Inc., acquired by GSE Power Systems, Inc. in December 1997, has been merged with and into GSE Power Systems, Inc. as of February 1998, with GSE Power Systems, Inc. being the surviving corporation. Name Jurisdiction of Organization - ---- ---------------------------- GS Information Systems FSC Ltd. Barbados GSE Systems International Ltd. State of Delaware MSHI, Inc. State of Virginia GSE Power Systems, Inc. State of Delaware GP International Engineering & Simulation, Inc. State of Delaware GSE Services Company L.L.C. State of Delaware GSE Power Systems AB Sweden GSE Process Solutions, Inc. State of Delaware GSE Process Solutions B.V. Netherlands GSE Process Solutions Belgium N.V. Belgium GSE Process Solutions Singapore (Pte) Limited Singapore