To what extent do adolescents and their friends socialize each others' attitudes toward immigrants? Can friends' positive attitudes toward immigrants counter adolescents' negative attitudes toward immigrants, and do friends' negative attitudes decrease adolescents' positive attitudes? These questions were examined by following a large (N = 1,472) friendship network of adolescents (49.2% girls; M[subscript age] = 13.31 at first measurement) across three annual measurements. Selection and influence processes regarding tolerance and xenophobia were distinguished with longitudinal social network analyses, controlling for effects of age, gender, and immigrant background. Findings showed that friends' tolerance predicted increases in adolescents' tolerance and friends' xenophobia predicted increases in adolescents' xenophobia. Moreover, friends' tolerance predicted a lower likelihood of adolescents' xenophobia increasing. The current results suggest that interventions should distinguish between tolerance and xenophobia, as these appear to represent two separate dimensions that are each influenced in specific ways by friends' tolerance and xenophobia.