Cyberbullying among youth is an emerging public health concern that has a wide array of deleterious outcomes. The current meta-analytic review synthesized school-based cyberbullying prevention programs' impact on promoting cyber-bystander intervention among K-12 students. As a result of exhaustive searches and a thorough screening procedure, a total of 9 studies were identified as eligible. Meta-analytic synthesis of the 9 studies involving 35 effect sizes demonstrated that overall, the treatment effect was not statistically significant (g = 0.29, SE = 0.14, p = .07, 95% CI [-0.03, 0.61]). Findings of the moderator analyses suggest that incorporating an empathy activation component in the prevention program was associated with better program effectiveness in promoting cyber-bystander intervention. Further, older age was found to be associated with better program outcomes. Findings of the current meta-analysis provide important insight for developing cyberbullying prevention programs that promote cyber-bystander intervention.