Civic engagement in adolescence contributes to the positive development of young people and to the health of communities and societies. The present study examined how an open classroom climate and adolescent students' citizenship self-efficacy can promote their expectations to participate in civic activities. Multilevel Structural Equation Modelling techniques were used to examine data from a nationally representative sample of 3,352 Italian eighth-graders, controlling for students' socio-economic status. The results revealed that students' willingness to participate in civic activities, both at the individual level and at the classroom level, was positively influenced by an open classroom climate and that this influence was mediated by students' citizenship self-efficacy. Our findings suggest that an open classroom climate can help students to become civically and politically involved by fostering their citizenship self-efficacy. The results of the present study extend our understanding of civic engagement in adolescence and inform policies that aim to promote it.