A substantial empirical literature confirms an educational disadvantage for foreign‐born children that arrive in their host countries at older ages. In the presence of a negative correlation between parental education and age at immigration, estimates of the educational attainment age at immigration gradient, neglecting controls for parental education, will tend to overestimate this disadvantage. The results indicate a considerable overestimation (up to almost 28%) of the disadvantage for immigrant children that arrive at older ages. Moreover, a considerable portion (69%) of the total bias associated with omitted controls for parental education reflects the non‐random educational selection of immigrant parents across the age at immigration distribution.