Trauma is proposed as a key to understanding the development and persistence of conduct disorder, in conjunction with other contributing factors. Trauma history is virtually universal in this population, and trauma effects can help to account for many features of the disorder, including lack of empathy, impulsivity, anger, acting out, and resistance to treatment. The current standard of care fails to fully address trauma, which may partially explain the low success rate of extant treatment approaches. Trauma-informed models of conduct disorder are suggested. Research, prevention and treatment implications are discussed.