Although violence and homicide are more prevalent in Colombia, South America than the US, the role of psychosocial factors in the violent behavior of Colombian adolescents remains unclear. The aim of this longitudinal study was to examine the interrelation of domains of personality, familial, peer, and ecological variables associated with violence in a community sample of adolescents from various self-reported ethnic groups in Colombia. The sample consisted of 1,151 male adolescents selected from three Colombian cities. The participants were surveyed using structured interviews at two points in time over a 2-year interval. Data were collected concerning adolescent personal attributes, family characteristics, peer, and ecological factors, including drug availability and the prevalence of violence in the community. The dependent variable was the self-reported frequency of the adolescent's violent behavior. The results supported a model in which violent behavior was correlated independently over time with a number of risk factors from several domains. Evidence for the hypothesized mediated effects of the familial monitoring and bonding domain, the peer domain, the ecological domain, and prior victimization related to personal attributes and contemporaneous violence and the adolescent's violent behavior 2 years later was also found. The findings suggest the use of specific intervention procedures with adolescents to prevent their subsequent violent behavior.