ICF Investor Presentation Q4 2023

Cautionary statements Caution Concerning Forward-looking Statements Statements that are not historical facts and involve known and unknown risks and uncertainties are "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995. Such statements may concern our current expectations about our future results, plans, operations and prospects and involve certain risks, including those related to the government contracting industry generally; our particular business, including our dependence on contracts with U.S. federal government agencies; and our ability to acquire and successfully integrate businesses. These and other factors that could cause our actual results to differ from those indicated in forward- looking statements that are included in the "Risk Factors" section of our securities filings with the Securities and Exchange Commission. The forward-looking statements included herein are only made as of the date hereof, and we specifically disclaim any obligation to update these statements in the future. Note on Non-GAAP Measures The information presented in this presentation regarding certain unaudited adjusted results and certain historical adjusted results does not conform to generally accepted accounting principles in the United States (U.S. GAAP) and should not be construed as an alternative to our reported results determined in accordance with U.S. GAAP. ICF has included this non-GAAP information to assist in understanding the operating performance of the company. The non-GAAP information provided may not be consistent with the methodologies used by other companies to prepare similar non-GAAP measures. All non-GAAP information has been reconciled with reported U.S. GAAP under Appendix 1 and 2 of this presentation. Additionally, ICF does not reconcile its forward-looking non-GAAP financial measures to the corresponding U.S. GAAP measures, due to the variability and difficulty in making accurate forecasts and projections and because not all of the information necessary for a quantitative reconciliation of these forward-looking non-GAAP financial measures (such as the effect of share-based compensation or the impact of future extraordinary or non-recurring events like acquisitions) is available to ICF without unreasonable effort. For the same reasons, ICF is unable to estimate the probable significance of the unavailable information. ICF provides forward-looking non- GAAP financial measures that it believes will be achievable, but it cannot accurately predict all of the components of the adjusted calculations, and the U.S. GAAP financial measures may be materially different than the non-GAAP financial measures. 2 ICF

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