Adolescents have high rates of sleep disorders and substance abuse, both of which have been associated with deleterious effects on mood, attention, and behavior. This article reviews data on the prevalence of sleep disorders, substance abuse problems, and comorbid psychiatric conditions in the adolescent population. Studies have consistently demonstrated that the prevalence of sleep problems is under-reported in adolescents in both clinical and community samples. The bidirectional correlation between substance use and sleep disturbances is also discussed. Based on the findings presented here, the authors conclude that it is imperative to improve the detection and treatment of sleep problems in children and adolescents. By treating sleep disturbances and targeting poor sleepers with additional counseling and education regarding the risk of substance use, clinicians may be able to prevent or delay the adverse effects of addiction. At the very least, the presence of insomnia should alert clinicians to the need for further evaluation for drug and alcohol abuse.