This study examined the relations between specific forms of peer victimization, math self-concept, and math grades of 740 students. Results showed that, in boys, all forms of victimization did not affect grades, while in girls, a highly perceived social exclusion impacted grades. In boys, a highly perceived humiliation negatively affected self-concept, whereas a highly perceived social exclusion positively affected self-concept. Boys’ self-concept mediated the relations between social exclusion and grades as well as between humiliation and grades. In girls, a highly perceived happy slapping positively affected self-concept, and self-concept mediated the relation between a highly perceived happy slapping and grades.