The present study examined whether adolescent loneliness would be lower within the context of positive relationships with peers. The core conceptual model predicted that hypothesized links between peer-rated social behaviors or victimization and loneliness would be mediated by social acceptance. Relationship experiences (i.e., social acceptance, reciprocal liking, and romantic relationship history), also were hypothesized to serve as protective factors in the links between social behaviors/victimization and loneliness. Finally, we examined sociometric status group differences in loneliness. Participants were 2091 11th grade students (61 percent girls). As expected, adolescent loneliness was positively associated with shyness, even when social acceptance was controlled. Additionally, loneliness was positively correlated with victimization and inversely related to prosocial and disruptive behavior. The link between victimization and loneliness was fully mediated by social acceptance; no other mediational models were supported. Also, the three relationship experience variables were unique predictors of loneliness (with social acceptance explaining the bulk of the variance in loneliness). There was no evidence, however, that social acceptance moderated the links between social behavior or victimization and loneliness. Sociometric analyses revealed that neglected and shy-rejected, but not aggressive-rejected adolescents, were lonelier than average peers.