Compulsions are meant to relieve anxiety or to prevent a dreaded event. An adolescent or adult may recognize that the ritual is unreasonable or excessive, but that is not necessarily true for the young child. Children and adolescents will attempt to hide their rituals, although with more severe symptoms, this is not usually possible. To meet the diagnostic criteria for the disorder, the person must experience distress, spend more than 1 hour a day in either obsessions or compulsions, or experience significant interference in his/her life. This article reviews the phenomenology, causes, treatment, and outcome of children and adolescents with obsessive-compulsive disorder.