Using data from the International Civic and Citizenship Study, this quantitative study explores the potential for open classroom climates to foster political efficacy and civic knowledge among 8th grade students in 14 Western European countries. Findings show that an open classroom climate is associated with increased civic knowledge and political efficacy. In addition, civic knowledge and political efficacy are positively correlated with social movement citizenship. However, the relationships between both political efficacy and civic knowledge on social movement citizenship are strengthened with presence of an open classroom climate. This study demonstrates the importance of an open classroom climate to develop students' knowledge and efficacy related to active citizenship.