An extensive literature demonstrates the relationship between academic self-concept and academic achievement, but the relationship between non-academic subdomains of the self and academic success in children and adolescents remains less clear. The current study examined longitudinal associations between social and behavioral self-concept, mental health symptoms, and indicators of academic achievement. Children (n = 364) from 36 classrooms across five elementary schools participated in the study. Children reported attitudes about the self, and teachers assessed children’s mental health symptoms and academic functioning at two time points. Structural equation models indicated that behavioral self-concept predicts subsequent academic engagement and study skills in low-income urban youth through improvement in academic self-concept and reduction in mental health symptoms. Findings point toward the potential promise of non-academic self-concept as a target for intervention to improve youth academic outcomes.