This study examined the hypotheses that (a) intimacy of friendship is more integral to socioemotional adjustment during adolescence than preadolescence, and (b) that competence in close relationship skills is more important during adolescence than preadolescence. Subjects were 102 10-13-year-old preadolescents and 70 13-16-year-old adolescents. Self- and friend ratings of friendship intimacy were gathered using a 2-step procedure ensuring that students rated only reciprocated friendships. Self- and friend ratings of close relationship competence were gathered using the newly developed Adolescent Interpersonal Competence Questionnaire. Intimacy of friendship was consistently and moderately correlated with adjustment and competence among adolescents but less consistently related among preadolescents. Significant age differences in coefficients were predominantly found for correlates of self-reported rather than friend-reported intimacy. Overall, the findings support the view that the ability to establish close, intimate friendships becomes increasingly important during early adolescence.