Attention-deficit hyperactivity disorder (ADHD) is a common co-occurring mental disorder among patients with substance use disorders (SUD). Clinicians must be cognizant of the complicated nature of diagnosis and treatment of ADHD when comorbid with SUD. Pharmacotherapy remains the mainstay of treatment for ADHD, although complementary psychotherapeutic approaches have been developed. Psychostimulant medications are the most commonly used medications to treat ADHD, but many clinicians are reluctant to prescribe stimulants to patients with SUD. Recommendations for treatment planning and clinical management for patients with co-occurring ADHD and SUD are discussed.