Behavioral problems in schools can cause serious harm to the emotional and social well-being of students and limit their ability to achieve their full academic potential. A prior pilot study on the universal application of Coping Power showed a significant decrease in the hyperactivity behaviors of five classes. The next step was to test whether Coping Power Universal could be successfully implemented by teachers in a variety of Italian schools. The sample involved 40 third- and fourth-grade classes (901 students) from public schools located in three Italian cities. Twenty classes were randomly assigned to Coping Power Universal, and 20 classes were randomly assigned to the control group, which received the strictly standard academic curriculum of Italian elementary schools. At each assessment period, the teachers completed the Strengths and Difficulties Questionnaire. The findings showed a significant reduction in hyperactive and inattention behaviors and conduct problems and emotional symptoms in the intervention classes compared with the control classes. This study suggests that Coping Power model can be delivered in school settings at both universal and targeted prevention levels and that in this multi-tiered prevention model, teachers can learn a set of intervention skills which can be delivered with flexibility, thus reducing some of the complexity and costs of schools using multiple interventions.