The purpose of this report is to provide evidence of an association between within-person variability in diurnal testosterone over 1 year, lifetime exposure to violence, and the manifestation of antisocial behavior in 135 pubertal-aged adolescents across 1 year. Adolescents' sex and lifetime history of violence exposure moderated the association between within-person variability in diurnal testosterone and antisocial behavior. Furthermore, sex-stratified analyses revealed that lifetime history of exposure to violence moderated the association between within-person variability in diurnal testosterone and antisocial behavior in females only. This report is unique in that it illuminates sex differences in within-person associations among exposure to violence, individual variability in diurnal testosterone, and antisocial behavior.