The associations of adolescents' psychosocial adjustment and relationship qualities with parents and peers have been widely studied; however there has been little concern on the possible impact of adolescents' psychosocial adjustment on parents' use of peer management behaviors. The specific aim of this study was to assess these relations and the mediating role of mothers' efficacy and concerns about adolescents' friendships on the relationships among adolescent adjustment, having prosocial and deviant friends and mothers' peer management behaviors. For this aim, Tilton-Weaver and Galambos's (2003) proposed model was adapted and adolescents' perceived loneliness introduced to the model. As a part of a project about the psychosocial development in adolescence, 297 seventh-to-tenth grade students and their mothers participated in this study in Ankara. Results revealed that adolescent aggression and loneliness predicted mothers' peer management on different dimensions. Adolescent aggression predicted mothers' "communications of disapproval" positively, whereas adolescents' perceived loneliness predicted mothers' communication about "supporting friendships", "preferences", and "disapproval" negatively. In addition, a series of regression analyses indicated the mediator role of mothers' concerns about their adolescents' friends. Accordingly, when adolescents reported lower levels of loneliness, mothers reported fewer concerns and communicated more about supporting friendships. Similarly, as adolescents reported having more prosocial friends, levels of mothers' concern was lowered and mothers communicated more about supporting friendships. Although, the predictive values are moderate, findings revealed the importance of mother's concern about adolescent's friendships in the quality of relationships among adolescent, peer, and mother.