This paper presents the results from a systematic and meta-analytical review of the effectiveness of cyberbullying intervention and prevention programs. Systematic searches were conducted for published and unpublished studies from 2000 to end 2017 on several online databases, including Web of Science, Scopus, PsychINFO, PsychARTICLES, Google Scholar, DARE, and ERIC. In addition, specific journals, for example, Cyberpsychology, Behavior, and Social Networking and Computers in Human Behavior, were hand searched for relevant studies. In total, 192 studies were retained for further screening from nearly 4000 search results. To be included in the present systematic review, studies had to: (1) include an adequate operational definition of cyberbullying; (2) describe the evaluation of an intervention or prevention program implemented with school-aged participants; (3) Employ experimental and control conditions; (4) Measure cyber-bullying behaviors using quantitative measurement instruments; and (5) have been published from 2000 onwards. Following rigorous screening, 24 publications were included in our systematic review. The majority of these studies (n = 15) used randomized controlled trials (RCTs) to evaluate anti-cyberbullying programs, while the remaining studies used quasi-experimental designs with before and after measures (n = 9). Within these 24 publications, 26 independent evaluations were reported. We conducted a meta-analysis to synthesize the results of primary evaluations of cyberbullying intervention programs. Our meta-analysis included 18 and 19 independent effect sizes for cyberbullying perpetration and cyberbullying victimization independently. The results of our meta-analysis suggest that cyberbullying intervention programs are effective in reducing both cyberbullying perpetration and victimization. Our results indicate that anti-cyberbullying programs can reduce cyberbullying perpetration by approximately 10%-15% and cyberbullying victimization by approximately 14%. We also compared results between different methodological designs and models of meta-analysis. The effect sizes were greater for RCTs than for quasi-experimental designs. Overall, the results of the present report address a significant gap in the cyberbullying literature, and suggest that intervention and prevention can be effective. However, future research needs to address the specific components of interventions that are effective, the effectiveness of prevention programs with non-school-aged samples, and the influence of overlapping offline and online victimization.