Adolescents and young adults with substance use disorders (SUD) and attention deficit/hyperactivity disorder (ADHD) are increasingly presenting in clinical practice. The overlap and role of treatment for these co-occurring disorders remains unclear. A review of the literature was conducted to highlight and update recent evidence on the overlap of ADHD and SUD, the role of ADHD medication on later SUD, and the treatment of ADHD and SUD in adolescents and young adults. Recent work continues to highlight the high risk for comorbid ADHD in patients with SUD; and conversely, the high risk for SUD developing in ADHD across the lifespan, particularly in the context of comorbid conduct disorder. Although the data remains discordant, it appears that ADHD pharmacotherapy does not increase the risk for SUD. Medication treatment alone does not appear to be particularly effective in treating SUD in currently active substance abusing individuals with ADHD. Structured therapies may be effective in treating adolescents and young adults with ADHD and SUD. Further controlled trials evaluating the sequence and effect of structured psychotherapies and/or ADHD pharmacotherapy on SUD relapse in these groups are warranted.