This article uses an educational effectiveness approach to model the impact of student, school, and educational system characteristics on several cognitive and non-cognitive student outcomes related to citizenship education. Using multivariate multilevel analysis, data from the International Association for the Evaluation of Educational Achievement (IEA) International Civic and Citizenship Education Study (ICCS) 2009 were analyzed, encompassing 102,396 lower secondary-school students (14-year-olds) in 4,078 schools in 31 countries. The results indicate that schools have a small influence on students' civic knowledge and hardly an impact on civic attitudes and intended civic behavior. Civic competences are mainly explained by individual student characteristics and out-of-school factors. Factors at the school level that were found to make a difference in students' civic competences are related to stimulating a democratic classroom climate in which free dialogue and critical debate on controversial political and social issues are encouraged, nurturing positive interpersonal relationships and creating opportunities for students to learn and practice democracy.