This article reviews the epidemiology and development of juvenile violence, together with key risk factors and risk assessment. Juvenile violent offenders tend to be persistent or frequent offenders with concurrent problems. There is considerable continuity from childhood aggression to juvenile violence, and an early age of onset of violence predicts a large number of violent offenses. The major risk factors are individual (high impulsiveness and low intelligence), family (parental criminality, poor supervision, harsh discipline, child maltreatment, disrupted families, large family size, and family poverty), peer delinquency, gang membership, urban residence, and living in high crime neighborhoods. New longitudinal studies focusing specifically on juvenile violence are needed to advance knowledge of this subject.