This study investigates the role of neighborhoods in adolescent violence in poor neighborhoods in San Juan, Puerto Rico. The study is part of a larger longitudinal project examining risk and resilience in adolescents' ages 12 to 15 years old and their caregivers. Using a cross-sectional design, a self-completion questionnaire, and an interviewer questionnaire, the authors assessed violent behaviors among participants across demographics, characteristics, and neighborhood social disorganization using the concepts of physical disorders and social disorder. Adolescent violence was positively associated with social disorder. The finding that adults in these neighborhoods walk around with visible firearms and engage in fighting, may have led adolescents to perceive that violence is an accepted behavior. Furthermore, socially disorganized neighborhoods might be less likely to organize on their own behalf because the occurrence of negative experience limits the amount of social support and resources that are available in the neighborhood.