A sample of 815 Dutch pupils from 49 classes was followed from age 6 (Dutch Grade 3) through age 11 (Grade 7) to estimate growth trajectories for pupils with different socio-ethnic backgrounds. The results indicate that the disadvantage for spelling already present in Grade 3 increases more strongly for Dutch low-socioeconomic status (SES) pupils than for low-SES minority pupils. With regard to mathematics, the initial disadvantage of Dutch low-SES pupils hardly changes, whereas the gap is clearly reduced for low-SES minorities. Effects of classroom composition appear to be quite modest, but classes with very high proportions of low-SES minority pupils show a clear disadvantage for both spelling and mathematics at age 6. In subsequent grades, the spelling gap between advantaged and disadvantaged classroom populations disappears completely. For mathematics, the gap is initially reduced to some extent, but at age 11 the disadvantage increases again.