Adolescence is an important period for the development of relationships between immigrants and non-immigrants, yet little is known about how problematic personality traits affect adolescents’ relationships with and attitudes toward immigrants. This work identified the roles of intergroup relationships and one dimension of problematic personality traits, namely callous–unemotional traits, in the development of adolescents’ tolerance and prejudice. Three annual measurements of a large community sample (N = 1,542) of non-immigrant adolescents (M
age = 15.31 at first measurement; 50.2 % girls) were used to show that tolerance and prejudice toward immigrants represent two dimensions with distinct developmental trajectories from early to late adolescence. Callous–unemotional traits predicted fewer decreases in prejudice toward immigrants, yet were not directly associated with tolerance. Intergroup friendships predicted stronger increases in tolerance, which, in turn, predicted decreases in prejudice toward immigrants. Thus, tolerance and prejudice toward immigrants seem to be differentially influenced by social experiences and problematic personality traits.