Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including additional amendments thereto) with respect to the shares of Common Stock, par value $0.01, of GSE Systems, Inc., a Delaware corporation. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: October 11, 2024