This study examined an ecological perspective on the development of antisocial behavior during adolescence, examining direct, additive, and interactive effects of child and both parenting and community factors in relation to youth problem behavior. To address this goal, the authors examined early adolescent dispositional qualities as predictors of boys' antisocial behavior within the context of parents' knowledge of adolescent activities and neighborhood dangerousness. Antisocial behavior was examined using a multimethod latent construct that included self-reported delinquency, symptoms of conduct disorder, and court petitions in a sample of 289 boys from lower socioeconomic status backgrounds who were followed longitudinally from early childhood through adolescence. Results demonstrated direct and additive findings for child prosociality, daring, and negative emotionality, which were qualified by interactions between daring and neighborhood dangerousness, and between prosociality and parental knowledge. The findings have implications for preventive intervention approaches that address the interplay of dispositional and contextual factors to prevent delinquent behavior in adolescence.