Housing is tied to neighborhoods. Therefore, to understand how housing affects health and health equity, the role of neighborhood environments must be considered. This article is a critical review of the relationship between neighborhoods and health. We discuss inequality among US neighborhoods and the roots of that inequality. We then explore the ways in which neighborhood environments may shape health, review the evidence about these effects, and discuss policy responses. Many studies document an association between neighborhoods and physical and mental health, and a few studies suggest that some of these relationships are causal. Thus, the evidence suggests that interventions at the neighborhood scale can potentially help advance health equity. Further research on the long-term impacts of neighborhoods on health and more rigorous studies of the impact of particular neighborhood interventions are needed. To advance health equity, policy makers also need to better understand the institutional arrangements and social policies that have created neighborhood inequality and pursue innovative approaches to changing them.