DREAMS (Determined, Resilient, Empowered, AIDS-free, Mentored and Safe) is a public-private partnership to reduce rates of HIV among adolescent girls and young women (AGYW) in the highest HIV burden countries. The Population Council had dual roles in the DREAMS partnership. We led the DREAMS implementation science research portfolio examining program effects and strategies for reducing HIV risk among AGYW and their male partners, with funding from the Bill & Melinda Gates Foundation and Project SOAR (funded by the United States Agency for International Development and the President’s Emergency Plan for AIDS Relief). Council experts, with funding support from Girl Effect and Project SOAR, also worked to strengthen the capacity of local organizations to design and implement programs focused on building girls’ social and protective assets necessary for a healthy transition into adulthood.