Childhood behavior problems affect long-term school success. Turkish immigrant mothers report higher levels of family adversity and are less involved in their children's school matters than German mothers. High family adversity is associated with delegation of parenting responsibilities and with elevated levels of behavior problems in childhood and adolescence. This study examined associations between family adversity, parental involvement in school matters, and Turkish immigrant (n = 148) and German (n = 54) students' teacher-rated behavior problems. Results showed that children whose parents were less involved in school were rated as more difficult by their teachers, whereas a Turkish immigrant background had no significant effect. Effects of high family adversity on teacher-rated behavior problems were fully mediated by parental involvement in school matters: teachers rated those children and adolescents as more difficult whose parents were less involved in school matters because they were living under adverse circumstances. In addition, analyses on the subsample of Turkish immigrant mothers showed that good German language abilities predicted higher involvement in school matters and were thus indirectly associated with more positive teacher judgments of children's behavior. Our study confirms the unique importance of parental involvement for children's school success and also points to potential avenues to prevent academic underachievement.