Objective: Rates of sexually transmitted infections (STIs) among adolescents are on the rise. The majority of adolescents who contract STIs do so through risky sexual behavior. Previous literature has identified multiple correlates of risky sexual behaviors among adolescents, including physical and sexual victimization, mental health concerns, and substance use. Few studies, however, have examined these relationships together in a comprehensive model. The primary purpose of this study was to examine whether relationship violence was related to risky sexual behavior, and whether mental health symptoms and substance use mediated this relationship. Method: A cross-sectional design was used, and adolescent females (N = 179), recruited from social service agencies, were 18.9 years old on average and were 37.2% White, 19.3% Black, 37.9% multiracial, and 5.6% other. Results: Regression results revealed that females who were physically assaulted and sexually victimized by their intimate partners did engage in more sex without condoms. Mediational analyses indicated that PTSD symptoms significantly influenced the relationship between (1) physical assault and risky sexual behavior and (2) sexual victimization and risky sexual behavior. Conclusion: Contrary to expectations, PTSD may act to reduce risk perhaps by reducing interest in sex. It is important to address victimization, PTSD, and sexual risk in young women. More work is needed to understand these complex relationships using longitudinal designs.