Maternal substance abuse is a critical problem, and adolescent mothers appear to be at high risk for such behaviors. We review studies on postpartum adolescent substance use to explore the extent of this problem and avenues for new research. Authors screened 1,300 studies, identifying 12 articles on substance use among postpartum adolescent mothers for this review. Adolescent mothers reported greater substance use before pregnancy compared to other adolescent females. Although some adolescents continued substance use during pregnancy, most stopped using only to resume within six months after birth. Comparisons of use to national samples of nulliparous adolescent females showed a higher prevalence of substance use in this population. Substances used often varied by race/ethnicity, with white mothers more likely to smoke cigarettes and use marijuana, and Black mothers more likely than whites to drink and use drugs. Of all identified studies, only one focused on Hispanics. Beliefs about drug use grew less negative as girls transitioned from pregnancy to parenthood. As they transitioned to adulthood, substance use remained prevalent and stable. Psychological distress and low self-esteem appeared to influence continued use. Friends' cigarette smoking predicted early initiation of and persistent smoking, while increased education predicted quitting. Early initiation of substances often predicted problem behaviors. Adolescent mothers are a vulnerable population, implicating use of problem behavior theory or the self-medication hypothesis in future research. Multiple avenues for new studies are needed to help identify effective treatment and intervention for this understudied population.