The article presents selected results of a reconstructive study on the significance of the peer group for children's educational biography. Based on the analysis of qualitative interviews and group discussions with c. 11-year-old children from different educational milieus in Germany it is first shown how, in general, groups of friends in different social contexts exert influence on the children's school careers. In a second part, the text pursues the question of how children produce social inequality themselves, what processes of distinction they practise and on the basis of which traits and criteria. Thereby the study demonstrates that internal and external distinction practices refer to entirely different concepts of achievement. (Contains 2 notes.)