The purpose of the current investigation was to examine if autonomic nervous system reactivity moderated the association between relational victimization and two established outcomes of peer maltreatment, anxious/depressive symptoms and anxious rejection sensitivity. A total of 119 female (M[subscript age] = 12.47, SD[subscript age] = 1.96) attendees of a residential summer camp participated. Participants' skin conductance and respiratory sinus arrhythmia were assessed during a laboratory stress protocol. Counselors reported on participants' relational victimization and anxious/depressive symptoms. Anxious rejection sensitivity was measured via self-report. Relational victimization was positively associated with both anxious/depressive symptoms and anxious rejection sensitivity among girls who exhibited reciprocal sympathetic nervous system (SNS) activation (i.e., high SNS reactivity and parasympathetic nervous system [PNS] withdrawal). Relational victimization was also positively associated with anxious/depressive symptoms among girls who exhibited reciprocal PNS activation (i.e., low SNS reactivity and PNS activation), although this effect was smaller in magnitude than findings for girls who exhibited reciprocal SNS activation. Results underscore the biosocial interactions between relational victimization and physiological reactivity in the prediction of anxious/depressive symptoms and anxious rejection sensitivity.