This study investigates the extent to which girls' better school attainment is associated with sex differences in intelligence, personality and school‐related motivation. In a sample of 1353 Austrian pupils (mean age 13.74 years), intelligence, the Big Five of personality, self‐esteem, school anxiety, school‐related intrinsic motivation and achievement goals were assessed as predictors and GPA as achievement criterion. Most predictors yielded significant mean differences between sexes and some of the variables predicted school achievement only for boys or only for girls. Intelligence and self‐esteem were the strongest predictors of GPA for both sexes, and school‐related intrinsic motivation, school anxiety and performance‐avoidance goals explained additional variance in GPA only for boys, whereas work avoidance did so only for girls. Copyright © 2008 John Wiley & Sons, Ltd.