Oppositional defiant disorder (ODD) is a disruptive behavior disorder characterized by a pattern of angry or irritable mood, argumentative or defiant behavior, or vindictiveness lasting for at least six months. Children and adolescents with ODD may have trouble controlling their temper and are often disobedient and defiant toward others. There are no tools specifically designed for diagnosing ODD, but multiple questionnaires can aid in diagnosis while assessing for other psychiatric conditions. ODD is often comorbid with attention-deficit/hyperactivity disorder, conduct disorder, and mood disorders, including anxiety and depression. Behavioral therapy for the child and family members improves symptoms of ODD. Medications are not recommended as first-line treatment for ODD; however, treatment of comorbid mental health conditions with medications often improves ODD symptoms. Adults and adolescents with a history of ODD have a greater than 90% chance of being diagnosed with another mental illness in their lifetime. They are at high risk of developing social and emotional problems as adults, including suicide and substance use disorders. Early intervention seeks to prevent the development of conduct disorder, substance abuse, and delinquency that can cause lifelong social, occupational, and academic impairments.