Research has indicated that there are several common pathways through which children and adolescents develop conduct disorder, each with different risk factors and each with different underlying developmental mechanisms leading to the child's aggressive and antisocial behavior. The current article briefly summarizes research on these pathways, including one that onsets in adolescence and seems to be an exaggeration of normal adolescent rebellion against authority. The other two pathways typically involve conduct problems that onset early in childhood but differ on whether the child shows significant levels of callous-unemotional traits or whether the child shows significant problems in emotional and behavioral regulation. Important directions for future research on these pathways are highlighted, as well as implications of these pathways for assessing and diagnosing children and adolescents with conduct disorder. In particular, diagnostic criteria should recognize the importance of callous-unemotional traits for distinguishing a distinct subgroup of youths with the disorder. Finally, implications for the prevention and treatment of conduct disorder are discussed, especially the need for interventions that are comprehensive and individualized to the characteristics of children and adolescents in the various developmental pathways.