Using a questionnaire-based study, we assessed the parent-reported prevalence of attention-deficit hyperactivity disorders (ADHDs), autism spectrum disorders, and obsessive-compulsive disorders in a group of 351 males with Duchenne muscular dystrophy. Of the 351 males with Duchenne muscular dystrophy, 11.7% were reported to have a comorbid diagnosis of ADHD, 3.1% had autism spectrum disorder, and 4.8% had obsessive-compulsive disorder. It can be concluded that the incidence of these neuropsychiatric disorders is higher in Duchenne males than in the normal population. This finding, together with recent reports on the higher prevalence of cognitive and learning problems in Duchenne, supports the view that Duchenne muscular dystrophy is not only a muscular disorder but also a disorder affecting the brain. It is important for clinical practice to take in account this heightened association. More research is needed to examine this association and its consequences.