Medical and health educational services are insufficient to control AIDS risk behavior. A new conceptual model that can guide more effective behavioral change strategies for whole communities is required to modify sexual practices and control the AIDS epidemic. We integrated learning theories with an ecological model to create a behavioral-ecological conceptual model of sexual risk behavior. We assumed a developmental process of learning and ongoing social influence. Contingencies of reinforcement and other motivational variables operate among sexual partners, their peers, and family networks in the context of culture. Our model hierarchically arrays learning processes within common social institutions (e.g., schools). Making appropriate changes in numerous social institutions concurrently may culminate in sufficient change in theoretical independent variables to establish safer sexual practices in whole communities. Application to adolescents' sexual development is used to illustrate this model. The behavioral-ecological model suggests that multiple interventions, with emphasis on change in social networks, is necessary to control the AIDS epidemic. If this model is correct, traditional education interventions will fail to ensure safer sexual practices among adolescents and adults.