Attention deficit hyperactivity disorder (ADHD) persists into adulthood in at least 30% of cases. Some individuals are only diagnosed in adulthood, and many are not diagnosed at all. Difficulty accessing medical care for adults with ADHD appears to be an international problem. In Australia, transition of older adolescents with ADHD to adult care is a major problem, and there is no uniform approach or standard process for referral to adult services. The Australian healthcare system presents some opportunities, but also some particular challenges, for developing innovative and equitable models of transition. In this paper, the challenges in achieving transition to adult care for patients with ADHD will be discussed, with a focus on the Australian system, and recommendations for assisting with transition and optimising support will be presented.