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Personality traits and social, emotional, and behavioral (SEB) skills share the same behavioral referents, but whereas traits refer to a person’s typical or average performance, skills refer to their capacity or maximal performance. Given their shared behavioral foundations, an important question to address is whether personality traits and SEB skills independently predict important outcomes. In this study (N = 642), we examined whether subscales of the Behavioral, Emotional, and Social Skills Inventory (BESSI), a measure of SEB skills, provided incremental validity in the prediction of the ACT composite score, an important academic outcome for American adolescents, over the Big Five personality traits. Consistent with our expectations, on average, SEB skills showed stronger associations with ACT achievement scores than personality traits. Moreover, SEB skills added incremental validity over and above personality traits in predicting ACT achievement scores. The findings reinforce the importance of conceptually distinguishing and measuring traits and skills.