Introduction: The present study examined the efficacy of the universal prevention version of the Coping Power Program in reducing behavioral and emotional problems and in promoting prosocial behaviors in middle-school classrooms. Methods: The study used a randomized control study design; and the sample included 839 middle-school Italian youths (411 males), attending 40 middle-school classrooms. The students were in seventh or eighth grade, and they had an average age of 13.24 years (SD = 0.65; range 12-14 years). Ninety students were Africans, the rest were Caucasian. Teachers and parents completed the Strengths and Difficulties Questionnaire, before and after intervention. We used the 24-session universal prevention adaptation of Coping Power, which aims to improve children's emotional regulation and social problem-solving skills. Results: Linear mixed models and effect sizes indicated that behaviors improved as a result of the Coping Power intervention. Specifically, the program was effective in reducing internalizing problems and increasing prosocial behaviors. Conclusions: The Coping Power Universal effectively adapts an existing evidence-based program, and is believed to be a useful strategy also to improve social emotional skills in middle-school students.