Based on the unique clinical correlates of two subtypes of childhood aggression (reactive and proactive), this study examined possible differential treatment effects for children with varying degrees of reactive or proactive aggression receiving one of two types of psychosocial treatment aimed at addressing these unique characteristics. Forty-seven affectively dysregulated children with oppositional defiant disorder (ODD) participated in the study. Results suggest a main effect for type of treatment, modest support for the moderating role of proactive aggression, and no support for reactive aggression as a moderator of treatment outcome. Implications for assessment and treatment of aggression are discussed.