AbstractCyberviolence among teenagers is a persistent problem addressed by several prevention programmes. In this article, we evaluate an educational intervention programme based on a serious game (CyberSafe Tool) that addresses cyberviolence against women and girls. The goal of the intervention and the serious game was to raise young people’s awareness of online violence against women and girls and to promote safe and responsible online behaviour. The intervention, conducted between 2020 and 2021, included 959 teenagers between 13 and 16 years old from Italy, Greece, Estonia and the United Kingdom. We used a survey questionnaire to conduct an impact assessment. It was administered three times – before the intervention, immediately after the intervention and three weeks after the intervention – to identify participants’ attitudinal changes. The results indicate significant positive attitude changes after the intervention that remained unchanged after the third questionnaire, which was administered three weeks after the intervention.