Investigated the interplay of family support and peer modeling on adolescent alcohol, tobacco, and marijuana use and gang involvement within an ecosystemic model. The predominantly Hispanic sample of 236 eighth-grade students attended a public middle school in a high-density, impoverished Miami neighborhood, characterized by high rates of criminal activity, substance abuse, and other stressors, placing the adolescents at risk for negative developmental outcomes. The participants reported the level of perceived social support they received from family members and rates of drug use and gang, involvement for themselves and for peers. The results showed that family social support reduced the influence of deviant peers on some of the problem behaviors reported by these adolescents, specifically tobacco and marijuana use. Deviant peer modeling was strongly associated with levels of adolescent problem behavior for tobacco, alcohol and marijuana use and gang involvement.