The current article presents results of the first large-scale study of adaptation of migrant children in Russian schools. The author analyze broad empirical material to discussed different issues of ethnic and social differentiation of schools, interaction between migrant parents and schools and between children of different nationalities, school teachers’ attitudes toward children of a different ethnicity. The method of multilevel regression was used to demonstrate the influence of immigration and ethnic status on academic performance of school children. It is shown that migrant children of ethnic minorities have a high level of motivation and their academic achievements are not lower than their local counterparts at the same schools; educational plans of migrant children do not differ from those of the ethnic majority. The analysis of communication networks in a classroom shows the absence of discrimination of ethnic minorities by the ethnic majority.