In explaining why girls outperform boys in school, some studies focus on individual gender-identity. Others stress the interactional dimension of students exerting pressure to act in a more masculine/feminine way. Still other research examines the development of student cultures in specific school contexts. Considering the gender structure, this study aims to understand gender differences in educational engagement by looking at the three dimensions of gender -- individual, interactional and institutional -- simultaneously. Stepwise multilevel analyses of data of 5162 students in 57 Flemish secondary schools, show that girls are more engaged in class activities than boys. The gender gap gets significantly larger with higher levels of traditional gender-role-attitudes (considered here a reflection of the institutional dimension) -- making boys less engaged. Second, boys display significantly more disruptive behaviour. This gender gap gets larger with higher levels of gender pressure (interactional dimension) and, above all, traditional gender-role-attitudes -- both making boys misbehaving more.