Evidence suggests that cyberbullying among school-age children is related to problem behaviors and other adverse school performance constructs. As a result, numerous school-based programs have been developed and implemented to decrease cyberbullying perpetration and victimization. Given the extensive literature and variation in program effectiveness, we conducted a comprehensive systematic review and meta-analysis of programs to decrease cyberbullying perpetration and victimization. Our review included published and unpublished literature, utilized modern, transparent, and reproducible methods, and examined confirmatory and exploratory moderating factors. A total of 50 studies and 320 effect sizes spanning 45,371 participants met the review protocol criteria. Results indicated that programs significantly reduced cyberbullying perpetration (g = -0.18, SE = 0.05, 95% CI [-0.28, -0.09]) and victimization (g = -0.13, SE = 0.04, 95% CI [-0.21, -0.05]). Moderator analyses, however, yielded only a few statistically significant findings. We interpret these findings and provide implications for future cyberbullying prevention policy and practice.