Immigrant adolescents have been found to show high levels of friendship homophily (the tendency to prefer intra-ethnic over interethnic friends). Based on acculturation theories, we predicted longitudinal changes and interindividual differences in level and rate of change in friendship homophily by immigrant composition of school, parental objections to the cultural adaptation of their offspring, discrimination, and language use. Altogether 218 newcomer and 272 experienced adolescents who had emigrated from the former Soviet Union to Germany participated in 4 annual assessments. Friendship homophily was assessed by percentage of intra-ethnic friends. Results revealed higher levels of friendship homophily among newcomer (75%) than among experienced (65%) adolescents at Time 1, and a significant decrease over time was found only among newcomers. Higher age, higher percentage of immigrants at school, and lower levels of new language use all related to higher friendship homophily. Rate of change in friendship homophily was strongly related to change in new language use. Findings suggest that friendship formation with native adolescents is related to social learning processes, in which new language use plays a crucial role.