The present study used general growth mixture modeling to identify pathways of antisocial behavior development within an epidemiological sample of urban, primarily African American boys. Teacher-rated aggression, measured longitudinally from 1st to 7th grade, was used to define growth trajectories. Three high-risk trajectories (chronic high, moderate, and increasing aggression) and one low-risk trajectory (stable low aggression) were found. Boys with chronic high and increasing trajectories were at increased risk for conduct disorder, juvenile and adult arrest, and antisocial personality disorder. Concentration problems were highest among boys with a chronic high trajectory and also differentiated boys with increasing aggression from boys with stable low aggression. Peer rejection was highest among boys with chronic high aggression. Interventions with boys with distinct patterns of aggression are discussed.