Background: Cyberbullying is a serious threat to public health and teachers can play a key role in its detection, prevention and intervention. The present study evaluated the effectiveness of the RPC (“Relazioni per crescere”—Relationships to Grow) program, a short intervention, implemented at classroom level by trained teachers, aimed at improving awareness on cyberbullying and increasing proactive coping strategies to deal with cyberbullying behaviors. Method: The effectiveness of the RPC project was analyzed through an observational study (pre/post-intervention comparison), involving 898 Italian students of Lower Secondary schools (6th–8th grades). Results: Hierarchical logistic regression showed that after the intervention students were more likely to consider the different roles in cyberbullying (cyberbully, cybervictim, reinforce/assistant, defender and bystander/observer). In addition, hierarchical linear regressions highlighted an improvement of social coping and cognitive coping strategies after the intervention. Conclusions: RPC is a short, teacher-based program that can increase the awareness of cyberbullying among students and improves their effective coping strategies to address cyberbullying. Further research on the efficacy of short teacher-based programs would be worthwhile, given the limited financial and time resources of the schools, emphasizing the active and crucial role of teachers in tackling cyberbullying.