The paper examines educational potentials of "Facebook" groups that are created and managed by students without any involvement from teachers. The objective is to study student-managed "Facebook" groups as a "third space" between the institutional space of teacher-managed "Facebook" groups and the non-institutional, personal space of the "Facebook" network. The main study of the article examines six student-managed "Facebook" groups and provides an analysis of a total of 2,247 posts and 12,217 comments. Furthermore, the study draws on group interviews with students from 17 Danish upper secondary schools and a survey answered by 932 students from 25 schools. Based on the survey and interviews, the paper concludes that "Facebook" is an important educational tool for students in Danish upper secondary schools to receive help on homework and assignments. Furthermore, on the basis of the analysis of "Facebook" groups, the paper concludes that the examined "Facebook" groups can be characterised as a third space of "school life" where students blend their personal, social life with academic schoolwork.