Developmental scholars assert that parents are important in fostering prosocial behaviors in adolescents, but longitudinal investigations on this topic are limited. Participants consisted of 372 boys and 358 girls with a mean age of 10.84 years (SD = 1.57) at Wave 1 from a mostly middle class community in Spain. Across three successive years, participants completed measures of fathers' and mothers' warmth and strict control, sympathy, prosocial moral reasoning, and self- and peer-reported prosocial behaviors. Results showed that parental warmth, sympathy, and prosocial moral reasoning were predictive of prosocial behaviors. Further analyses showed bidirectional effects such that early prosocial behaviors predicted later parenting and adolescents' prosociality. Findings lend support to cognitive-developmental and moral internalization models of prosocial development. (Contains 1 table and 2 figures.)