Objective: The aim of the article is to review the evidence that aerobic exercise may be a useful adjunct treatment for ADHD. Method: Studies on physical, cognitive, and psychosocial aspects of aerobic exercise that are relevant to ADHD are reviewed and evaluated. Results: Stimulant medication, the main pharmacotherapy for ADHD, and aerobic exercise both act on catecholamine pathways. Aerobic exercise has been shown to be beneficial in preclinical studies on spontaneous hypertensive rats, an animal model of ADHD, and in clinical trials of children with ADHD, as an adjunct treatment to medication. Social and neurocognitive function in children and adults seem to be positively affected by exercise as well. Nevertheless, no controlled clinical trials in adults with ADHD have been conducted. Conclusion: Aerobic exercise may be a useful non-medication adjunct therapy for ADHD. The clinical effectiveness of aerobic exercise for ADHD in children and adults warrants further clinical studies.