Explanations about differences in drinking and smoking rates between educational tracks have so far mainly focused on factors outside the classroom. The extent to which these behaviors are rewarded with popularity within a classroom-so called popularity norms-and their interaction with individual characteristics could explain the observed differences in risk behavior. 1860 adolescents (M-age = 13.04; 50% girls) from 81 different classrooms reported three times during one academic year about their own and their classmates behavior. Overall, in vocational tracks popularity norms for alcohol and smoking were more positive and predicted classroom differences in alcohol and smoking. Knowledge about classroom processes can advance the field in unraveling the functional aspects of risk behavior in adolescence. Preregistration: The hypotheses and the analytical plan of this study were preregistered under number #39136 (https://aspredicted.org/blind.php?x=gx77p6).