This study examined the bidirectional development of aggressive response evaluation and decision (RED) and antisocial behavior across five time points in adolescence. Participants (n = 522) were asked to imagine themselves behaving aggressively while viewing videotaped ambiguous provocations and answered a set of RED questions following each aggressive retaliation (administered at Grades 8 and 11 [13 and 16 years, respectively]). Self- and mother reports of antisocial behavior were collected at Grades 7, 9/10, and 12 (12, 14/15, and 17 years, respectively). Using structural equation modeling, the study found a partial mediating effect at each hypothesized mediational path despite high stability of antisocial behavior across adolescence. Findings are consistent with an individual systems perspective by which adolescents' antisocial conduct influences how they evaluate aggressive interpersonal behaviors, which affects their future antisocial conduct.