Objective: Aggression Replacement Training (ART) is a multimodal program aiming at replacing antisocial behaviors by actively teaching desirable behaviors. The program is frequently used and has been provided within a wide variety of settings, but its effectiveness in its own right has not been addressed in previous reviews. This systematic review examines the effect of ART on antisocial behavior in young people and adults. Methods: Published and unpublished literature was searched to identify randomized and non-randomized studies comparing ART for adults and youth with usual care, other interventions, or no intervention. Primary outcomes included recidivism in antisocial behavior, while secondary outcomes were related to social skills, anger management and moral reasoning. Findings: This review identified 16 studies with considerable clinical and methodological diversity. The methodological quality and the post-intervention follow-up of the studies were limited. Almost half of the studies were conducted by researchers who have vested interests in the intervention. Conclusions: There is an insufficient evidence-base to substantiate the hypothesis that ART has a positive impact on recidivism, self-control, social skills or moral development in adolescents and adults. Further research is warranted by independent investigators exploring the effects of ART on clearly-defined target groups using high standard evaluation designs.