•SEB skills and personality traits both predict academic success in adolescence.•Skills and traits predict most academic outcomes similarly.•Skills add information beyond traits for predicting standardized test performance. The present research examined relations between social, emotional, and behavioral (SEB) skills, personality traits, and academic success in a sample of adolescents (N = 975). Results indicated that both skills and traits robustly predicted school grades, educational aspirations, and performance on a standardized achievement test, even after accounting for demographic characteristics. Moreover, skills and traits were often interchangeable: when assessed using the same cognitive, affective, and behavioral referents, they converged strongly and did not provide incremental validity over each other for predicting most outcomes. However, skills provided some incremental validity beyond traits for predicting standardized test performance. Taken together, these findings highlight the importance of SEB skills and personality traits for predicting and understanding academic success.