Behavioral science has a long history of engaging in efforts to understand and address socially important issues. Poverty and inequities in health and development are among the most important and complex social issues facing the world today. With its Sustainable Development Goals (SDGs), the United Nations (2015) has focused attention and guidance on addressing key global challenges, including to "end poverty" (SDG 1), "ensure good health and well-being for all" (SDG3), and "reduce inequality within and among countries" (SDG 10). In this paper, we provide a framework and illustrative examples of contributions of behavioral science to these issues. We feature illustrative behavioral interventions at the individual, relationship, community, and societal levels. We highlight the diversity of issues, intervention methods, and settings reflected in applications of behavioral science. By joining methods from behavioral science, public health, and other disciplines-and the experiential knowledge of those most affected by inequities-behavioral methods can make significant contributions to collaborative efforts to assure health and well-being for all.