The authors used Bronfenbrenner's conceptual framework of an ecological systems model to examine factors that are independently associated with sexually transmitted disease (STD) risk behaviors among 280 sexually active detained female adolescents. Using computer-assisted self-interviewing procedures, the authors assessed individual characteristics, peer relations, community factors, and media influences and their association to STD risk behaviors. Findings indicated that factors such as greater substance use, stronger risk-taking attitudes, lower perceived parental monitoring and familial support, gender roles supporting male dominance, risky peer norms, and lower student-teacher connectedness, were independently associated with increased STD risk behaviors. Findings suggest a multisystemic approach to STD prevention among this population.