This study investigates the influence of intelligence and motivation on school achievement in Math, German and English. Intelligence, conscientiousness, domain-specific ability self-perceptions and interest, goal orientations, self-efficacy, perfectionism and self-control of 109 eight graders were assessed and related to final grades in Math, German and English. The correlations between school achievement and most assessed constucts were rather strong. Moreover, especially girls' school achievement was predicted by intelligence, motivation and partly by indicators of effort, such as doing one's homework. Intelligence was the strongest predictor of grades in all domains. In addition, domain-specific ability-self perceptions play an important role for the prediction of school-achievement. Grades in Math were also predicted by self-efficacy and self-control. In German, parental expectations could predict final grades, grades in English were also predicted by domain-specific interest. Intelligence and motivation could account for a great deal of criterion variance.