This paper explores the impact of the hidden curriculum on students. The hidden curriculum refers to the social relations and school climate of the schools. Two theories are presented as the basis for studying the relationship between school climate and students' social beliefs and actions. The generalization theory states that students view the school as a small version of society, and that they transfer their political and social beliefs developed in school to the outside world as well. The congruence theory is based on the relationship between what students are directly taught in classes and what they learn indirectly through interaction with the school authority structure. The bulk of the paper reviews more than 30 research studies about the relationship between school political climate and student attitudes and behavior. Results include the following: (1) in schools with high degrees of student participation in governance, students had high levels of political efficacy and trust, (2) teachers' support of student involvement in school affairs and school climate is related to political efficacy, (3) open classroom climate appears to foster positive political attitudes, and a closed climate is associated with negative attitudes, and (4) participation in school discussions and debates is related to higher levels of civic competence. Although some studies did not find such positive relationships, it is apparent that school and classroom climate are correlates of student political attitudes. Social studies educators should be especially aware of this when they plan course content, discussion of controversial issues, and political participation projects. (AV)