Selection and influence processes in academic achievement—More pronounced for girls?

•We study selection and influence effects based on academic achievement.•We expect selection and influence to be stronger among girls than among boys.•We find strong and similar influence effects among boys and girls.•We find strong selection effects among girls but no selection effects among boys.•Our findings highlight the importance of studying gender-specific network behavior. Friends tend to be similar in their academic achievement. In this study, we investigate whether this similarity results from students selecting friends with similar achievement or from friends influencing students’ achievement. In particular, we argue that selection and influence effects should be stronger among girls than among boys. Using friendship network data on 1273 German secondary school students and stochastic actor-oriented models for the co-evolution of networks and behavior, we find selection effects only among girls, which is in line with our theoretical arguments. By contrast, influence effects contribute to achievement similarity among both boys and girls.