EDUMIGROM survey data demonstrates that the impact of ethnic segregation/separation of students in school is far from evident. Various patterns of separation affect students’ performance, self-esteem and aspirations towards further schooling and labour market participation quite differently, and, naturally, the wider social and structural circumstances seem to have a determining influence as well. The research reveals a divergence between new and old member states of the European Union in how ethnic background and school environment affect students’ performance, self-esteem, and aspirations. In new EU member states, there are significant differences between ethnic minority and majority students studying in the same environment. In particular, ethnic background as well as the ethnic composition of a school influence students’ performance, self-esteem, and aspirations. While old EU member states are by no means homogeneous, these relationships are generally not so pronounced.