Objective: In this study, I examined the association between age of substance use initiation and sexual violence (SV) among adolescent girls. Methods: Data were drawn from the 2017 Youth Risk Behavior Survey, and the sample included 7526 girls. Logistic regression was used to estimate the relationship between age of initiation of alcohol use, marijuana use and cigarette smoking, and SV, assessed by forced sexual intercourse and experiencing SV. Results: A dose-response association was observed between age of substance use initiation and SV. Across all 3 substance use variables and for both SV outcomes, those who initiated substance use before age 15 were more likely to experience SV than those who initiated at or after age 15, who, in turn, had a higher likelihood of experiencing SV than those who had never initiated substance use. Conclusion: Early initiation of substance use may be a meaningful marker of risk for SV victimization in later adolescence. SV prevention programs could use early initiation of substance use to identify adolescents who are at increased risk for SV and provide them with targeted interventions. To be more effective, primary prevention of SV may need to begin targeting substance use in early adolescence.