This chapter addresses the influence that government has on children's development. Government exerts its influence as part of the social ecological macrosystem through direct funding of programs, laws that constrain or encourage behavior, support for research, and the creation of institutions to uphold laws or implement policies. Because government's roles are to affect both the mean and the distribution of outcomes for children, we focus on the problem of poverty, its impact on children, and ways government tries to buffer children from those outcomes. After providing a history of government policies that affect families and children, we synthesize the state of knowledge about how specific public policies in domains such as health, education, and social services affect children's development. We ground this synthesis in relational developmental systems theory, which asserts a bidirectional relation between a child and his or her context. We describe methods that developmental scientists use to study public policies. We highlight the contemporary challenge of optimizing children's development in a context of economic uncertainty, federal deficit, and an aging population. Finally, we argue that children's development can be optimized through more systematic, evidence‐based policy making that is grounded in developmental science.