Engineering AND EXPERT STAFFING Platform For THE POWER AND PROCESS Industries INVESTOR PRESENTATIONNASDAQ: GVPSeptember 25, 2019

FORWARD LOOKING STATEMENTSand non-gaap financial measures This presentation, our remarks, and answers to questions contain statements that are considered forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934. These statements reflect our current expectations concerning future events and results. We use words such as "expect," "intend," "believe," "may," "will," "should," "could," "anticipate," and similar expressions to identify forward-looking statements, but their absence does not mean a statement is not forward-looking. These statements are not guarantees of our future performance and are subject to risks, uncertainties, and other important factors that could cause our actual performance or achievements to be materially different from those we project. For a full discussion of these risks, uncertainties, and factors, we encourage you to read our documents on file with the Securities and Exchange Commission, including those set forth in our periodic reports under the forward-looking statements and risk factors sections. We do not intend to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.This presentation, our remarks, and answers to questions include references to adjusted EBITDA, adjusted net income, and adjusted earnings per share (“adjusted EPS”), which do not adhere to generally accepted accounting principles (“GAAP”). We define EBITDA as earnings before interest, taxes, depreciation and amortization (“EBITDA”). References to Adjusted EBITDA exclude non-cash loss on impairment, impact of the change in fair value of contingent consideration, restructuring charges, stock-based compensation expense, impact of the change in fair value of derivative instruments, and acquisition-related expense. References to Adjusted net income exclude non-cash loss on impairment, impact of the change in fair value of contingent consideration, restructuring charges, stock-based compensation expense, impact of the change in fair value of derivative instruments, acquisition-related expense, and amortization of intangible assets related to acquisitions. We define adjusted EPS as adjusted net income divided by fully diluted shares of common stock issued and outstanding. EBITDA, Adjusted EBITDA, adjusted net income, and adjusted EPS are reconciled to net income, the most directly comparable GAAP measure, in the financial tables included in the Appendix to this presentation. We believe that this additional information and the reconciliation we provide may be useful to help evaluate our operations. This information supplements our results as reported in accordance with GAAP and should not be viewed in isolation from, or as a substitute for, our GAAP results.With respect to Adjusted EBITDA on a forward-looking basis and as a combined company following certain recent acquisitions, a reconciliation of the difference between this non-GAAP expectation and the corresponding GAAP measure (expected net income) is not available without unreasonable effort due to potentially high variability, complexity and low visibility as to the items that would be excluded from the GAAP measure in the relevant future period, such as unusual gains and losses, adjustments to the provision for income taxes, depreciation of fixed assets, amortization of intangibles, costs related to restructuring actions and interest expense, and certain anticipated cost synergies, the impact and timing of potential acquisitions and divestitures, and other structural changes or their probable significance. The variability of the excluded items may have a significant, and potentially unpredictable, impact on our future GAAP results.Unless otherwise indicated, all results of operations and the financial condition of the Company are as of June 30, 2019 and all market data set forth in this presentation is as of September 23, 2019. We undertake no duty to update or revise the information in light of new information, future events or otherwise, although we may do so from time to time as management believes is appropriate. Any such updating may be made through the filing of reports or documents with the Securities and Exchange Commission, through press releases or through other public disclosures. 2

Who Is GSE SYSTEMS? 3 We provide engineering and highly-skilled personnel to the global power and process industriesPerformance Improvement SegmentWe are a market leader in simulation and engineering programs for the nuclear/fossil power industry We provide computer-based tutorials and simulators to the process industryNuclear Training & Consulting SegmentWe staff nuclear power plants with specialized personnel, primarily in white-collar training and operating roles Our solutions enhance employee and plant performance, reduce risk, increase revenue and lower costs for clients Ticker | Exchange GVP | Nasdaq Headquarters Maryland Number of Employees ~475 Recent price1 (9/23/19) $1.93 Shares outstanding ~20M Market cap1 (9/23/19) ~$39M Total cash1 (6/30/19) ~$10M Total debt1 (6/30/19) ~$21M Enterprise value1 ~$46M Revenue (LTM) ~$90M EV / Revenue1 ~0.5x 1 Enterprise Value and EV/Revenue are estimates based on the Recent Price, Market Cap, Total Cash and Total Debt amounts as of the dates provided herein and do not represent the Enterprise Value or EV/Revenue as of the date of this presentation.

Annual Financial Highlights1,2,3 Revenue (in $M) Gross Profit (in $M) Adjusted EPS (Diluted)1 +25% CAGR 4 +21% CAGR 4 Adjusted EBITDA (in $M)1 1 Adjusted EBITDA and Adjusted EPS are non-GAAP financial measures; see GAAP to non-GAAP reconciliation in Appendix; 2 Only includes Absolute Consulting from September 20, 2017, True North from May 11, 2018 and excludes DP entirely. 3 Fiscal year ended December 31, 2018 is unaudited4 CAGR = Compound Annual Growth Rate +$11.7M Improvement +$0.54 Improvement 4

Pro-Forma Revenue MIX – ~$90M (LTM) Performance Improvement Nuclear Training & Consulting By Segment By Industry Nuclear Fossil North America Europe By Geography Utilities Other By End-User Asia Non-Power / Process 5

6 Business Model – How we make Money ~50%30-40+%Engineering Modeling & Modification ServicesFixed price, and time and material contractsPercent complete, or as service is performed billing occurs ~50%12-15%Technical / High-Value StaffingTime and material contractsAs service is performed billing occurs <5%80-90%SoftwareSale of perpetual license with recurring MX, or SaaS annual subscriptionLicense upon delivery, ratable recognition over life of MX agreement Performance Improvement Nuclear Training & Consulting Software1 % of Revenue:Gross Margin:Primarily Selling:Business Model:Accounting: 1 Software is a component of GSE’s Performance Improvement segment

Investment Highlights 7 Expertise from 40+ years of serving clients in the power and process sectorsProven and differentiated technology for simulation and training solutionsDifficult-to-replicate technology and base of talented, specialized employees Leadership with an “owner/operator” mentality Experience and skill-set to deliver operational improvementsTrack record of building companies through successful M&A transactions Highly Specialized Platform 40+ years serving a high-barrier-to-entry market Strong, enduring relationships with blue chip power and process companies Aligned, ProvenLeadership Significant discount relative to industry peers Blue Chip Client Base Attractive Valuation Focused on delivering strong organic growth from underlying core businessPowerful long-term acquisition platform in place to consolidate a fragmented industry Compelling, Scalable Acquisition Platform Landscape targeted for roll-up includes markets with combined size of $4+ billionFavorable industry drivers: recognition of nuclear as a critical source of resilient baseload energy; aging workforce crisis; rising demand for carbon-free electricity Large Addressable Markets

GSE SENIOR Leadership 8 Kyle Loudermilk – President & CEO20+ years of executive experience at publicly-listed MicroStrategy and AspenTech, and PE-backed Datatel/Ellucian (Thoma Bravo and Hellman & Freidman)Strong track record revitalizing technology companiesBS, MS, Chemical Engineering – Columbia UniversityHarvard University General Management ProgramEmmett Pepe – CFO, CPA30+ years of experience in finance management across a variety of business sectors Focus on the software and telecommunications industriesExecutive positions at MicroStrategy, BroadSoft, Software AG, and webMethodsBS, Accounting – Penn State UniversityBahram Meyssami – CTO25 years of experience in the software industryFormer positions at Aspen Technology, Datatel, University of MarylandBS, MS, Ph.D Chemical Engineering – University of MarylandPaul Abbott – President, Nuclear Industry Training and Consulting Division 33 years of experience in nuclear training, consulting and operations Principal of Hyperspring since 2007; former senior reactor operator at two different U.S. nuclear facilities Previously served in the U.S. NavyBS, Nuclear Engineering Technology – Excelsior College August 2015 July 2016 December 2015 November 2014

Highly educated, Specializedemployee base (~475) 9 Performance Improvement Nuclear Training & Consulting Nuclear/Fossil Non-Power / Process Corporate Employees ByTechnical Focus Employees By Industry/Function

Representative Blue chip customers x 10 The trademarks above are the property of the referenced companies; GSE disclaims ownership of such marks. Inclusion of a representative customer herein is not intended to suggest endorsement or recommendation.

EV/SALES (TTM)1 2-3x ~1.0x >5x EV/EBITDA (TTM)1,2 10-12x 10-12x >15x Attractive Valuation relative to PEERS 11 PEERS: Performance Improvement Nuclear Training & Consulting Software 1 Normalized average historical trading multiples for peers2 EBITDA is a non-GAAP financial measure

Pause in Acquisitions - Focusing on Operations and Organic Growth 12 Today: We remain committed to delivering long-term profitable growth and increasing shareholder value through both organic and inorganic initiatives. Past: Future:

Long-term Opportunity to utilize GSE as an Acquisition Platform 13 Core focus: understand the vendor ecosystems in our target markets – look for asymmetrical risk/reward acquisitions $10-50M30-40%70+Fixed price, and time and material contracts $10-80M12-15% 100+Time and material contracts $5-15M 75-85%30+ Sale of perpetual license with recurring MX, or SaaS annual subscription Performance ImprovementTargets Nuclear Training & Consulting Targets SoftwareTargets Typical Rev. Range:Gross Margin:# of Opportunities:Business Model: $10-60M15-25% 50+Fixed price, and time and material contracts EPC for Transmission and Distribution

Landscape Targeted for Roll-Up: Markets of SIGNIFICANT Size Global Market1 US Market1,2 1 Source: Company estimates based on various publicly available resources and proprietary research2 Only includes white collar labor Global Market1 Global Market1 Performance ImprovementTargets Nuclear Training & Consulting Targets SoftwareTargets EPC for Transmission and Distribution 14

What is driving MARKET demand? Growing awareness of the value and resiliency factor of nuclear power as a source of baseload carbon-free energyWidening skills gap and aging workforce—a significant issue in the US power industryIncreasing demand for carbon-free electricity, such as nuclear powerJapan’s restart of nuclear reactors post-FukushimaInitiatives such as “Delivering the Nuclear Promise” Emerging capex cycle driven by the digitalization of the nuclear industry 15 1 Source: NEI, September 20152 Source: NEI estimates per Power Engineering magazine, February 2015 “Nuclear energy is America’s top source of carbon-free electricity and avoids more than 1/2 billion tons of carbon emissions each year.”1 “39% of the nuclear workforce will be eligible for retirement by 2018, which means the industry must hire 20,000 new workers to replace those retiring workers.”2 X

Nuclear Leads the Way in CO2 Emissions Avoided By the U.S. Power Industry1 16 1Source: Nuclear Energy Institute Inc., Nuclear By The Numbers (March 2019) Million Metric Tons, 2018 2018 US Emissions-Free Electricity Fuel CO2 Emissions Avoided by the U.S. Power Industry Nuclear Energy = Clean Air

Robust Nuclear INDUSTRY Benefits GSE 17 1Source: International Atomic Energy Agency-Power Reactor Information System (March 2019); 2Source: World Nuclear Association, August 2017 TODAY NEAR TERM LONGER TERM Global nuclear reactor installed base1: 445 Ongoing fees for maintenance, re-hosting, retuning, model upgrades, training Nuclear reactors under construction1: 53 New nuclear capacity needed by 2050 to meet Harmony vision2: 1000 GW New simulator sales +Incremental fees for maintenance, re-hosting, retuning, model upgrades New simulator sales+Incremental fees for maintenance, re-hosting, retuning, model upgrades Nuclear Units Under Construction by Country Operable Nuclear Reactors – Top 10 Countries Projected New Capacity (GW per Year) Required to Meet Harmony Targets3 GSE’s opportunity:

Existing U.S. Nuclear Fleet has 20-40+ Years of further lifespan 18 Plants here for long term: Assuming an average nuclear plant license spans 60 years, the existing fleet requires 20+ years of continuing services, and 40+ years if and as licenses get extended to 80 years. The Average U.S. Nuclear Plant is 37 Years Old1 Number of U.S. Nuclear Plants per Age Group1 GSE provides essential services and technology to the aging U.S. nuclear fleet to improve operations, enhance safety and extend plant life. 1Source: The Conversation, August 2018; International Atomic Energy Agency Years Lifespan

Investment CONCLUSIONS 19 GSE is an engineering and expert staffing company focused on the power and process industries Proven simulation and training technology with a highly-specialized employee base Large addressable markets supported by favorable industry drivers Enduring relationships with blue-chip clients developed over 40+ years Strong leadership team aligned with shareholders, driving a new growth plan Powerful, scalable acquisition platform in place to enhance growth and build shareholder value

20 Engineering AND EXPERT STAFFING Platform For THE POWER AND PROCESS Industries Q&A

21 APPENDIX

GSE SYSTEMS Financial History1 22 1 Excludes DP Engineering for periods prior to February 15, 2019; excludes True North prior to May 11, 2018 and excludes Absolute Consulting prior to September 20, 2017 2 Non-GAAP financial measure; see GAAP to non-GAAP reconciliation on following pages Financial Summary1 Fiscal Year Ended 6 Months Ended (in $ millions, except shares amounts) 2015 2016 2017 2018 Jun. 30 2018 Jun. 30, 2019 Revenue 56.8 53.1 70.9 92.2 47.6 45.7 Gross Profit 12.9 16.3 18.5 23.1 11.2 10.6 Gross margin 23% 31% 26% 25% 24% 23% Operating (loss) income (4.1) 1.6 0.2 1.4 (0.4) (5.3) Operating margin (7%) 3% 0% 1% (1%) (12%) Net (loss) income (4.7) 1.4 6.6 (0.4) (0.5) (4.4) Diluted EPS ($0.26) $0.08 $0.33 ($0.02) ($0.03) ($0.22) Diluted shares 17,892,891 18,512,266 19,605,427 19,704,999 19,580,046 19,979,018 EBITDA 2 (3.0) 2.8 1.5 3.7 0.3 (3.8) Adjusted EBITDA 2 1.8 5.0 5.7 7.4 3.2 2.1 Adjusted net income 2 0.5 4.0 3.0 4.7 2.9 2.6 Adjusted EPS – diluted 2 $0.03 $0.21 $0.15 $0.24 $0.14 $0.13 Balance Sheet (in $ millions) Jun. 30, 2019 Cash and cash equivalents 9.7 Current assets 30.9 Total assets 69.0 Current liabilities 20.4 Total debt 20.9 Total stockholders' equity 27.6

GSE SYSTEMS eBITDA and Adjusted EBITDA reconciliation (in $ Thousands)1 23 EBITDA and Adjusted EBITDA are not measures of financial performance under generally accepted accounting principles ("GAAP"). Management believes EBITDA and Adjusted EBITDA, in addition to GAAP measures, provide meaningful supplemental information regarding our operational performance. Our management uses EBITDA, Adjusted EBITDA, and other non-GAAP measures to evaluate the performance of our business and make certain operating decisions (e.g., budgeting, planning, employee compensation and resource allocation). This information facilitates management's internal comparisons to our historical operating results as well as to the operating results of our competitors. Since management finds these measures to be useful, we believe that our investors can benefit by evaluating both non-GAAP and GAAP results. Investors should recognize that EBITDA and Adjusted EBITDA might not be comparable to similarly-titled measures of other companies. These measures should be considered in addition to, and not as a substitute for or superior to, any measure of performance prepared in accordance with GAAP. A reconciliation of non-GAAP EBITDA and Adjusted EBITDA to the most directly comparable GAAP measure (net income) in accordance with SEC Regulation G follows: 1 Excludes DP Engineering for periods prior to February 15, 2019; excludes True North prior to May 11, 2018 and excludes Absolute Consulting prior to September 20, 2017 Adjusted EBITDA Summary Fiscal Year Ended 6 Months Ended (in $ thousands) 2015 2016 2017 2018 Jun. 30, 2018 Jun. 30, 2019 Net (loss) income (4,705) 1,422 6,557 (354) (515) (4,361) Interest (expense) income, net (88) (85) (80) 268 39 524 (Benefit) provision for income taxes 471 350 (6,153) 1,131 (190) (1,442) Depreciation and amortization 1,328 1,080 1,146 2,634 944 1,477 EBITDA (2,994) 2,767 1,470 3,679 278 (3,802) Loss on impairment - - - - - 5,464 Change in fair value of contingent consideration 849 (207) 446 - - (1,200) Write-down of capitalized software development costs 1,538 - - - - - Restructuring charges 1,791 490 778 1,269 1,107 2 Stock-based compensation expense 541 1,550 2,472 1,526 1,028 1,036 Impact of the change in fair value of derivative instruments 40 18 (99) 350 247 8 Consulting support for finance restructuring - 394 - - - - Bad debt related to customer bankruptcy - - 122 85 65 - Acquisition-related expense - - 473 540 491 628 Adjusted EBITDA 1,765 5,012 5,662 7,449 3,216 2,136

Adjusted Net Income and Adjusted EPS reconciliation (In $ Thousands, except share amounts)1 24 Adjusted Net Income and adjusted earnings (loss) per share (“adjusted EPS”) are not measures of financial performance under generally accepted accounting principles (“GAAP”). Management believes adjusted net income and adjusted EPS, in addition to GAAP measures, provide meaningful supplemental information regarding our operational performance. Our management uses Adjusted Net Income and other non-GAAP measures to evaluate the performance of our business and make certain operating decisions (e.g., budgeting, planning, employee compensation and resource allocation). This information facilitates management's internal comparisons to our historical operating results as well as to the operating results of our competitors. Since management finds these measures to be useful, we believe that our investors can benefit by evaluating both non-GAAP and GAAP results. Investors should recognize that Adjusted Net Income and Adjusted EPS might not be comparable to similarly-titled measures of other companies. These measures should be considered in addition to, and not as a substitute for or superior to, any measure of performance prepared in accordance with GAAP. A reconciliation of non-GAAP adjusted net income and adjusted EPS to GAAP net income, the most directly comparable GAAP financial measure, is as follows: 1 Excludes DP Engineering for periods prior to February 15, 2019; excludes True North prior to May 11, 2018 and excludes Absolute Consulting prior to September 20, 2017 Adjusted Net Income (Loss) Summary Fiscal Year Ended 6 Months Ended (in $ thousands, except shares amounts) 2015 2016 2017 2018 Jun. 30, 2018 Jun. 30, 2019 Net (loss) income (4,705) 1,422 6,557 (354) (515) (4,361) Loss on impairment - - - - - 5,464 Change in fair value of contingent consideration 849 (207) 446 - - (1,200) Write-down of capitalized software development costs 1,538 - - - - - Restructuring charges 1,791 490 778 1,269 1,107 2 Stock-based compensation expense 541 1,550 2,472 1,526 1,028 1,036 Impact of the change in fair value of derivative instruments 40 18 (99) 350 247 8 Consulting support for finance restructuring - 394 - - - - Acquisition-related expense - - 473 540 491 628 Amortization of intangible assets related to acquisitions 494 289 335 1,612 462 1,056 Bad debt related to customer bankruptcy - - 122 85 65 - Tax reform impact - - 2,497 - - - Release of valuation allowance - - (10,555) (339) - - Adjusted net income (loss) 548 3,956 3,026 4,689 2,885 2,633 Earnings (loss) per share - diluted (0.26) 0.08 0.33 (0.02) (0.03) (0.22) Adjusted earnings (loss) per share - diluted 0.03 0.21 0.15 0.24 0.14 0.13 Weighted average shares outstanding - diluted 17,892,891 18,512,266 19,605,427 19,922,151 19,920,034 20,154,866

contacts 25 Kalle Ahl, CFA (212) 836-9614kahl@equityny.comDevin Sullivan(212) 836-9608dsullivan@equityny.com Kyle Loudermilk, CEO(410) 970-7800kyle.loudermilk@gses.com