It is well established that girls outperform boys in schools, but the available empirical evidence suggests that the determinants of the gender achievement gap are poorly understood. The present paper looks inside families for explanations. Rich data for families with children in the lower secondary school in Norway are used to investigate whether parents' allocations of educational efforts are biased by gender. It is shown that parents allocate more efforts to girls than to boys, and also, that there is a negative correlation between parental efforts and prior achievements. The compensating resource allocations are more evident for boys than for girls. (Contains 9 tables and 1 figure.)