A 12-week, 32-lesson afterschool intervention was conducted with third-to fifth-grade urban African American boys classified as aggressive. Grounded in attribution theory and organized around the construct of perceived responsibility in self and others, the intervention focused on increasing both social skills and academic motivation. Participants (N = 64) were randomly assigned to an intervention or no-treatment control group. Boys in the intervention group showed an increase in social skills and academic motivation skills and were rated by their teachers as more cooperative and academically persistent. The implications of the findings for the design of interventions in urban schools are discussed.