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Abstract: Background: bullying (and cyberbullying) is a widespread phenomenon among young people and it is used to describe interpersonal relationships characterized by an imbalance of power. In this relationships often show aggressive behavior and intentional "harm doing " repeated over time. The prevalence of bullying among youth has been reported to vary widely among countries (5.1%-41.4%) and this behavior seems generally higher among student boys than girls. Sev-eral school interventions have been developed to reduce bullying, but reported inconsistent results possibly related to limi-tations in the study design or to other methodological shortcomings. Aims: evaluating randomized-controlled trials (RTCs) conducted between 2000 and 2013 to assess the effectiveness of school interventions on bullying and cyberbullying. Methods: a systematic search of the scientific literature was conducted on Pubmed/Medline and Ebsco online databases. We also contacted experts in the field of preventive bullying research. Results: 17 studies met the inclusion criteria. The majority of studies did not show positive effects in the long term; the interventions focused on the whole school were more effective in reducing bullying than interventions delivered through classroom curricula or social skills training alone. Conclusion: while there is evidence that programs aimed at reducing bullying can be effective in the short term, their long-term effectiveness has not been established, and there are important differences in the results based on gender