Sexual violence exposure represents a serious public health issue among female youth given its association with female youths' engagement in health-risk behaviours. Sexual minority female youth are particularly vulnerable to sexual violence exposure, alcohol use, suicidality, and sexual-risk behaviour. Using the population-based 2017 Youth Risk Behaviour Survey, we examined sexual violence as a mediator of sexual orientation disparities in health-risk behaviours among female youth. This study included 7,532 female students in grades 9 through 12 across the US. Participants identified their sexual orientation as heterosexual (73.5%); bisexual (12.2%); and, gay or lesbian (2.2%). Compared to heterosexual female youth, sexual violence exposure, alcohol use, binge drinking, and multiple sex partners were more common among bisexual female youth. The elevated risk of suicidality was most notable among gay or lesbian female youth relative to heterosexual female youth and bisexual female youth relative to heterosexual female youth. Mediation analyses showed that sexual violence exposure partially explained the sexual orientation disparity in these co-occurring health-risk behaviours between bisexual female youth and heterosexual female youth. Our findings highlight the need for clinical attention to be paid to assessing and treating the health effects of sexual violence, especially among bisexual female youth.