This study examined physiological correlates (cortisol and α-amylase [AA]) of peer victimization and aggression in a sample of 228 adolescents (45% male, 55% female; 90% African American; M age = 14 years, SD = 1.6 years) who participated in a longitudinal study of stress, physiology, and adjustment. Adolescents were classified into victimization/aggression groups based on patterns with three waves of data. At Wave 3, youth completed the Social Competence Interview (SCI), and four saliva samples were collected prior to, during, and following the SCI. Repeated-measures analyses of variance with victimization/aggression group as the predictor, and physiological measures as outcomes, controlling for time of day, pubertal status, and medication use revealed significant Group × SCI Phase interactions for salivary AA (sAA), but not for cortisol. The results did not differ by sex. For analyses with physical victimization/aggression, aggressive and nonaggressive victims showed increases in sAA during the SCI, nonvictimized aggressors showed a decrease, and the normative contrast group did not show any change. For analyses with relational victimization/aggression, nonaggressive victims were the only group who demonstrated sAA reactivity. Incorporating physiological measures into peer victimization studies may give researchers and clinicians insight into youth's behavior regulation, and help shape prevention or intervention efforts.