Good German language skills are necessary to succeed in the German educational system. E specially for children of immigrants, learning contexts outside the family like preschools can provide access to the German language during preschool age. However, international studies have shown that the impact of preschool attendance depends on the preschools' quality. This article analyses whether the time spent in preschool and the quality of its environment have a beneficial influence on 3-5-year-old children's German vocabulary development and whether these factors have a larger impact on children with a Turkish migration background compared to German children. The analyses are conducted with data from the project 'Preschool Education and Educational Careers among Migrant Children' which includes a two-wave panel over a one-year period. It is shown descriptively that Turkish children score worse on the German vocabulary test than German children at both points in time, but that they make greater progress. Using fixed effects regressions, it is demonstrated that longer preschool attendance leads to a significant improvement in the German vocabulary of Turkish children and that all children can profit from a better quality of the preschool environment. Thus, preschools turn out to be an important context for language learning-especially for Turkish children.
