There is growing evidence that participation in constructive leisure activities facilitates positive youth development. Empirical evidence also supports the influence of families and communities on positive developmental outcomes for adolescents. This study examined the relationship among attitudes toward family and community, participation in structured out-of-school activities, and pro-social behavior. As predicted, community aspects such as opportunities available and the attitudes the youth held toward the community, as well as their attitude toward family were predictive of activity involvement. Activity involvement, in turn, was predictive of pro-social behavior. Attitude toward family was also predictive of attitude toward the community. Attitude toward community was a direct predictor of the positive developmental outcome of pro-social behavior, although contrary to the original hypothesis, family influences did not have a direct effect on pro-social behavior. Implications for continued practice and change for a variety of sectors in the positive youth development field such as educators and educational institutions, youth-serving organizations, families, and policy makers are discussed, along with recommendations for continued research in this field.