We examined how final grades in mathematics and verbal arts in the first year of high school (Grade 11) were predicted in a Norwegian population by sex, previous grades in middle school (Grade 10), self-concept, self-efficacy at a domain-specific level, and intrinsic motivation. Direct and indirect relations were examined by means of a series of regression analyses. Participants were 483 students from six Norwegian high schools. End of term grades in high school correlated positively with grades in middle school in both mathematics (r = .62) and verbal arts (r = .55). The relation between grades at the two points of time was to a large extent mediated through mathematics, verbal self-concept, and self-efficacy. Intrinsic motivation also correlated positively with subsequent achievement (r = .63 and .42 in mathematics and verbal arts, respectively). However, intrinsic motivation had little predictive value for subsequent grades over and above the prediction made by self-concept and self-efficacy. Thus, self-concept and self-efficacy were the strongest predictors of subsequent grades. Predictions from the Internal/External frame of reference model were supported for self-concept but not for domain-specific self-efficacy.