Reducing the potential magnitude of the Department of Defense’s (DoD’s) per- and polyfluoroalkyl substances (PFAS) liability will require a sustained effort to identify the best technologies to characterize, treat, and manage these sites. Efficient and meaningful investigations will require significant improvements in the current understanding of PFAS toxicity and behavior in the environment, as well as improvements in sampling and analysis of PFAS. A substantial fraction of impacted sites will likely require remediation. Given the recalcitrance and complexity of PFAS, as well as the low cleanup levels likely to be required, advances in current remediation technologies are needed to improve effectiveness and greatly reduce costs. SERDP and ESTCP have funded hundreds of projects that have quickly and significantly advanced our understanding and management of PFAS in the environment. Our work evaluates a range of potential treatment technologies, ecotoxicological effects, and improved AFFF site characterization. An overview of these investments is shown below.