Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most frequent psychiatric disorders at school age. The core symptoms of hyperactivity, impulsivity and inattention emerge before the age of seven and are associated with severe impairment of the child's everyday functioning (family, school, leisure time). Seventy percent of the affected children show at least one comorbid psychiatric condition or learning disorder/academic impairment. ADHD is one of the most widely investigated disorders in child and adolescent psychiatry. A multitude of imaging (fMRI) and genetic studies comparing children with ADHD and typically developing children have provided clear evidence for the neurobiological foundation of ADHD. Nevertheless, environmental, familial and academic factors play an important role with regard to the persistence and severity of the disorder. Treatment should be preferentially multimodal, with interventions targeting the child, the parents, and, if possible, the teacher. Society with its specific requirements and constraints, and also school, are not well adjusted for children that are different, hyperactive and easily distracted. However, many of these children also have resources. When fascinated by a task, they may show persistence and commitment.