Comorbid psychiatric disorders and drug use disorders (DUDs) are common among adolescents with alcohol use disorders (AUDs). These comorbid disorders have a large potential significance on the clinical course of the AUDs among adolescents, and can predict a shorter time to relapse of alcohol use. The use of medication for treatment of the various comorbid adolescent populations has increased dramatically in recent years, despite the lack of double-blind, placebo-controlled studies that demonstrate their safety and efficacy. Consequently, to date, no empirically proven treatment exists for most of these comorbid disorders. This chapter reviews the state of the art regarding the treatment of comorbid adolescents. This chapter also identifies gaps in knowledge regarding the treatment of comorbid adolescents, and outlines directions for future research in this field.