This research examined how parent-adolescent communication about initiating sex and condoms influenced the relationship between peer norms and behavior. African American and Hispanic adolescents reported on parent-adolescent discussions about initiating sex and condoms, perceived peer norms about sex and condom use, and their own behavior. Communication about sex and perceived peer norms about sex were each related to sexual behavior, and communication about condoms and peer norms about condoms were related to condom use behavior. For both sex and condom use, the peer norm–behavior relationship was moderated by parental communication: Peer norms were more strongly related to behavior among adolescents who had not discussed sex or condoms with a parent. Communication was also related to teens naming a parent as their best source of information about sex. Results suggest that a lack of communication may cause adolescents to turn to peers and that peers may then influence their behavior.