Communities differ in the prevalence of various health behaviors, but it is not known to what extent these differences are due to "different types" of people living in them. We used data from the evaluation of the Henry J Kaiser Family Foundation Community Health Promotion Grant Program to study individual-level and community-level variation in health behaviors for 15 communities. Our results show (1) there was significant variation among these communities in prevalences of smoking, consumption of alcohol and dietary fat, and use of seatbelts; (2) these differences persisted after control for demographic, health status, and other health behavioral characteristics of the people in the communities; (3) the community effect on a particular person's behavior, as represented by R2, was very small (less than 1%); and (4) the adjusted differences in prevalences among communities were potentially large (for example, a 7 percentage point difference in the probability of smoking). Unique features of communities may influence health behaviors. These findings affirm the potential importance of contextual effects on individual health behavior and thus support the theory that changing the community environment may offer effective ways to change individual health behavior.