The present study examined gender differences in self-assessments for ten different facets of school-related social and learning behavior as well as for grades in math and German. The sample consisted of N = 3405 students (grades 4-12). The results showed that boys estimate almost all facets lower and score only higher in endurance than girls. Moreover, differences were found for grades in German in favor of the girls. Positive correlations with the grades were approximately equal in boys and girls. Both grades could be explained by positive assessments in cooperation, endurance and concentration, but also by negative assessments in diligence in learning. Good grades in math were also associated with high perceived Independence as well as with low assessments in self-awareness and empathy, whereas good grades in German were also related with low assessments in social contact.