This paper assesses whether chemically dependent adolescents with comorbid learning disorders (LDs) derived less effective treatment results when compared to chemically dependent adolescents without LD and examines the moderating effects of prior treatments, treatment length, and treatment completion. Two hundred one adolescents were recruited between 1992 and 1993 from Massachusetts residential treatment centers and subsequently followed up 6 months after enrollment. Compared to chemically dependent teenagers without LD, those with LD were twice as likely to re-use substances at least once by follow-up. LD teenagers were more likely to attend Alcoholics/Narcotics Anonymous if they had prior admissions to treatment programs and longer treatment length. LD teenagers who completed treatment also experienced a greater decrease in current depression compared to LD teenagers not completing the treatment. This study is the first to consider outcomes of substance abuse treatment for adolescents with LD and contributes to the growing literature on comorbidity and substance abuse treatment.