Individuals’ behavior change is affected by the environments in which they live. This chapter takes an ecological perspective on how interventions in community contexts can change individual behaviors related to physical and psychological outcomes. The chapter first outlines the concept of ecology before applying it to three approaches to changing behavior in the community context: (1) social norms; (2) social settings; and (3) social policy. Examples of community behavior change programs and research are given for each approach. In terms of social norms, the chapter discusses how research on interpersonal violence, sexual health, and alcohol use on college campuses has incorporated norms-based interventions to change people’s views of their own and others’ behavior. In terms of social settings, the chapter outlines a range of settings and highlights research on creation of food pantries as a community-based example of a means to combat food insecurity. With regard to social policy, examples are provided of community efforts to target changes in local policy. Last, suggestions for future research on behavior change interventions at the community level are provided. The lack of attention paid to ripple effects, the relationship between ecological levels, and methodological issues that make gathering data on community change challenging are discussed.