The research in the areas of peer, family and community environmental effects on adolescent substance use and misuse clearly and consistently shows that peer substance use behavior is the primary predictor of adolescent alcohol use. Peer norms, however, are more important in the prediction of adolescent alcohol misuse. Parental norms and monitoring are secondary to the peer variables, but still of significance in the prediction of adolescent alcohol use and misuse. The intrapersonal construct of susceptibility to peer pressure is as important as the peer and parent variables in the prediction of both alcohol use and misuse in adolescence.