The diagnosis of attention deficit hyperactivity disorder (ADHD) poses several diagnostic problems, as is widely acknowledged. The name points to two symptoms only, which are unspecific and embedded in many more neuropsychological symptoms. The additional deficits, such as problems with orientation, memory, cognition, emotion, autonomic nervous regulation, and motor dysfunctions, can be more important for patients in their daily lives than attention and hyperactivity. The general term “neurodevelopmental disorder (6A0)” in the International Classification of Diseases (ICD-11) is more appropriate and should be used instead. A further question is, when a dysfunction, such as inattention, becomes a clinical sign. As outlined in the International Classification of Functioning, Disability and Health (ICF), the context and the associated impairment decide on the clinical relevance of dysfunctions. Accordingly, the diagnosis of neurodevelopmental disorders must start with the description of context requirements, then assess capacity restrictions, and finally relate these to neuropsychological deficits. Subdimensions of neurodevelopmental disorders, as listed in ICD-11, are of no additional benefit, as they are comorbid merging syndromes.