Oppositional defiant disorder includes distinct but inseparable dimensions of chronic irritability and oppositional behavior. The dimensions have been identified in early childhood to adulthood, and show discriminant associations with internalizing and externalizing psychopathology. The introduction of disruptive mood dysregulation disorders and the requirements that it take precedence over oppositional defiant disorder diagnostically are not supported by evidence and introduce confusion about the structure and linkages of irritability and oppositional behavior, and obscure the importance of the behavioral dimension in explaining and predicting poor outcomes. A dimensional framework with irritability, oppositionality, callous-unemotional traits, and aggression may more fully describe antisocial outcomes.