The present study had three main objectives: (1) to develop and validate scales of young adult social competence in two domains, close relationships and social groups, using peer ratings of California Q-sort (Block, 1974;Kremen & Block, 2002) items; (2) to test the hypothesis that social competence is associated with young adult well-being and ego development; (3) to test the hypothesis that close relationship competence aligns more closely than social group competence with young adult functioning. Psychometric data on peer ratings of social competence are presented. For 133 young adults, peer ratings of social competence were correlated in expected directions with indices of functioning (e.g., self-worth, education, psychological distress, criminal behavior, and ego development). Associations were generally stronger for competence in close relationships than in social groups.Social competence refers to the ability to engage successfully in social interactions and interpersonal relationships, including the ability to express and interpret both verbal and nonverbal communication (e.g.,