A mediation model was tested whereby the degree to which adolescents perceived their parents as responding appropriately to their prosocial and antisocial behaviors was hypothesized to predict adolescents' tendencies toward prosocial behavior indirectly by way of adolescents' prosocial values. Adolescents (N = 140; M age = 16.76 years, SD = .80; 64 percent girls; 91 percent European Americans) completed measures of prosocial values and of the appropriateness with which they expected their parents to react to their prosocial and antisocial behaviors. In addition, teachers and parents rated the adolescents' tendencies for prosocial behaviors. A structural equation model test showed that the degree to which adolescents expected their parents to respond appropriately to their prosocial behaviors was related positively to their prosocial values, which in turn was positively associated with their tendencies to engage in prosocial behaviors (as reported by parents and teachers). The findings provide evidence for the central role of adolescents' evaluations and expectancies of parental behaviors and of the role of values in predicting prosocial tendencies. Discussion focuses on the implications for moral socialization theories and on the practical implications of these findings in understanding adolescents' prosocial development. Tables, figure, and references (Published Abstract)