This study examines social class differences in the gender segregation of children and pre-adolescents and draws upon data from two recent German studies. Based on longitudinal quantitative data from a representative children's survey, the first analysis suggests that in comparison to children from upper-class families, lower-class children tend to remain longer in gender-heterogeneous peer groups, a major proportion of students continue to have opposite-sex friends and changes between same- and opposite-sex peers appear earlier. In two further sections, material from a reconstructive study of 10- to 12-year-old pre-adolescents is used to describe more in-depth reflections of children themselves on gender segregation as well as orientations that develop in same-sex peer groups in contrasting social classes. (Contains 3 notes and 2 tables.)