Given the passivity of many adolescents upon witnessing peer victimization, the goal of this study was to evaluate the features of school-based peer victimization events that promote helping. A sample of 470 early adolescents (52% girls; 71% White, 9% Black, 6% Latino, 2% Asian, 1% American Indian, 8% Multiethnic, and 3% Other) reported likelihood of helping and specific helping and non-helping behaviors with an experimental vignette method and through descriptions of recently witnessed real-life victimization events. With both methods, an adolescent's relationship with the victim predicted likelihood of helping and specific helping behaviors above and beyond the contribution of other key personal characteristics including gender, empathy, communal goal orientation, and previous victimization experiences. Examination of adolescents' real-life experiences yielded systematic patterns between their responses and their reasoning about the responses undertaken. The results illustrate the relevance of taking into account peer victimization event characteristics for promoting witness intervention in adolescence. (Contains 3 tables and 1 figure.)