Objectives: To assess the efficacy of educational and skills-based interventions to prevent relationship and dating violence in adolescents and young adults. Methods: We searched Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, and other databases for randomized, cluster-randomized, and quasi-randomized studies of interventions to prevent relationship or dating violence. We conducted meta-analyses for episodes of relationship violence, behaviors, and attitudes. Results: We included 38 studies (15,903 participants) in this review, of which we included 33 studies in the meta-analyses. The risk ratio for episodes of relationship violence was 0.77 (95% confidence interval [CI]: [0.53, 1.13]). The standardized mean difference (SMD) for attitudes toward relationship violence was 0.06 (95% CI: [–0.01, 0.15]). The SMD for behavior related to relationship violence was –0.07 (95% CI: [–0.31, 0.16]). Subgroup analyses showed no statistically significant differences by setting or type of participants. Conclusions: We found no evidence of effectiveness of interventions on episodes violence, attitudes or behaviors.