The five U.S. Department of Defense (DoD) Regional Centers for Security Studies have been helping partner nations build strategic capacity for almost 20 years. However, recent DoD budget constraints have put pressure on the regional centers (RCs) to increase efficiency. The Office of the Secretary of Defense (OSD) asked RAND to conduct a study on the overall impact of the RCs, their effectiveness in advancing DoD policy priorities, the ways in which they assess their programs, and ways in which they could improve their impact and efficiency and the resulting outcomes. The RAND study team found that centers have had great success at the missions they have undertaken. They are high-impact components of U.S. security cooperation and engagement efforts, despite their relatively small budgets. The team identified 24 ways in which the centers advance U.S. interests, including building partner capacity, building relationships, fostering pro-U.S. outlooks, offering unique opportunities for engagement, and promoting regional dialogue that reduces tensions. However, RCs should improve impact-oriented data collection and analysis for improved assessment, methodically collecting such data over time. OSD and the combatant commands should improve their oversight and management of the RCs to ensure alignment with department- and theater-level objectives. In addition, OSD should maintain the RCs' focus on regional security challenges rather than refashioning them to address specific threats. Options to consider for greater impact include evaluating the balance between core residential courses and in-region workshops and determining whether and to what extent the centers should develop customized programs for DoD components so as to secure funds beyond the core budget they receive from OSD.