Purpose: This study explored the prevalence and stability of behavioral difficulties and self-concepts between the ages of 8 and 17 years in a sample of children with a history of specific language impairment (SLI). We investigated whether earlier behavioral, emotional, and social difficulties (BESD); self-concepts; and language and literacy abilities predicted behavioral difficulties and self-concepts at 16/17 years. Method: In this prospective longitudinal study, 65 students were followed up with teacher behavior ratings and individual assessments of language, literacy, and self-concepts at 8, 10, 12, 16, and 17 years. Results: The students had consistently higher levels than norms of 5 domains of BESD, which had different trajectories over time, and poorer scholastic competence, whose trajectory also varied over time. Earlier language ability did not predict later behavioral difficulties or self-concepts, but the prediction of academic self-concept at 16 by literacy at 10 years approached significance. Conclusions: The importance of distinguishing domains of behavioral difficulties and self-concept is demonstrated. Language, when measured at 8 or 10 years of age, was not a predictor of behavior or self-concepts at 16 years, or of self-concepts at 17 years. The study stresses the importance of practitioners addressing academic abilities and different social-behavioral domains in delivering support for adolescents with SLI.