This study assessed the similarity of adolescents and their friends and peer network associates in religiosity and the extent to which these relationships were associated with antisocial behavior. The sample included 1010 Indonesian (480 male, 530 female) 8th (13.37 years) and 10th grade (15.36 years) students. Adolescents were similar to their mutual friends and network associates (identified using Social Cognitive Mapping) in religiosity, and the religiosity of both friends and network associates added to male adolescents' self-religiosity in predicting antisocial behavior; these effects were not present for girls. Peers may associate with others similar to themselves in religiosity and these associations may partially explain why religious boys exhibit low levels of aggressive behavior.