This study examined the link between childhood sexual abuse and adolescent substance use among girls, and evaluated depressive self-concept and behavioral under-control (BUC) as pathways to substance use for sexually abused girls. Participants (n = 150) were drawn from a longitudinal study of the impact of domestic violence on the lives of women and children. Structural equation modeling revealed that girls' childhood sexual abuse was associated prospectively with their later substance use. This relationship persisted when age, co-occurring forms of child abuse (physical, exposure to domestic violence), childhood depression and aggression, family income, maternal substance use, and parenting practices were controlled. Behavioral under-control mediated the relationship between childhood sexual abuse and later substance use, but depressive self-concept did not. Implications, limitations, and directions for future research are discussed.KEY WORDS: sexual abuse; substance use; self-concept; problem behavior.