The indication for treatment of adult attention-deficit hyperactivity disorder (adult ADHD) is derived not from the diagnosis itself but results from the severity of symptoms, comorbidities, psychosocial consequences, and a lack of defined resources for ADHD. The basis of therapy is psychoeducation that includes teaching about symptoms, models of the disorder, and options for treatment. The combination of pharmacotherapy and psychotherapy is recommended. Methylphenidate is considered the first-line therapy, because of its strong effect and modest side effects, but is not authorized in Germany ("off-label use"). Atomoxetine, which is authorized for continuing treatment into adulthood, is indicated if methylphenidate is insufficient or has unacceptable side effects and in case of comorbid substance use. Various psychotherapeutic interventions using available ADHD-typical resources have demonstrated positive effects. Psychosocial support and self-help groups complete the treatment concept. Persistence of the treatment indication has to be reevaluated at regular intervals. Disorder-specific multimodal therapy of adult ADHD conforms to the complex, primarily neurobiologic etiology and the psychosocial consequences.