The major social science theories on adolescent risk-taking--strain, social control, and differential association theories--have received substantial empirical support. The relationships between variables central to these theories and individual differences in temperament related to risk-taking, however, have not been adequately studied. In a sample of adolescents, this study examines how behavioral inhibition and activation relate to variables central to social control, strain, and differential association theories and how interactions between behavioral inhibition and activation and these theories predict aggressive and nonaggressive forms of risk-taking. The results of this study suggest that (a) BIS (behavioral inhibition system) and BAS (behavioral approach system) are related to strain, social control, and differential associations; (b) the effects of these social science and personality variables are, at least partially, additive; and (c) significant interactions exist between BIS/BAS and social control and differential association. Combining social science and personality concepts therefore could advance the understanding of differences in risk-taking. (Contains 4 tables and 2 figures.)