The Population Council is building one of the world's largest bodies of research on programs to improve the lives of adolescents, especially girls. For the past two decades, the Council has been identifying best practices, refining the critical elements of girl-centered programs, and using rigorous evidence to help decisionmakers allocate scarce resources to the most effective programs. The Council's adolescent girls research portfolio is also supporting decisionmakers to formulate the most effective evidence-based policies to improve girls' lives and meet national development goals. This brief summarizes key findings from nine rigorous evaluations of empowerment and asset-building interventions for adolescent girls. It presents emerging findings, considers the implications of these findings for programs and investments, and documents future research questions to close evidence gaps. Drawing on recent findings from over 50,000 individuals from Latin America, sub-Saharan Africa, and South Asia, this brief synthesizes findings from the Council's research portfolio on adolescent girls. Each intervention/evaluation has been assigned a number that will be used throughout the brief and in the companion tables. Collectively, these evaluations provide evidence on whether a particular intervention, or a package of interventions, had an impact for adolescent girls within the areas of education, health (e.g., sexual and reproductive health), economic empowerment, social capital, gender-equitable attitudes, and violence. Some of the findings have already been published in peer-reviewed journals, while other results are preliminary and have yet to be peer reviewed. Five of the nine evaluations also consider costs and a cost assessment per girl served, which is an important consideration for replicating and scaling these approaches.