BackgroundSexual assault (SA) is experienced by a substantial proportion of emerging adult college students and is associated with elevated rates of Post‐Traumatic Stress Disorder (PTSD) and alcohol use. The current study examines the mediating role of posttraumatic stress symptoms (PTSS) in the associations among SA severity, drinking to cope with anxiety, and average weekly drinks while considering the moderating roles of gender identity and sexual orientation.Methods2160 college students diverse in gender (cisgender women, 64.4%; cisgender men, 30.6%, and transgender and gender diverse (TGD) individuals = 4.9%) and sexual orientation (heterosexual = 68.0%, LGBQ+ = 32.0%) completed measures of SA severity, PTSS, drinking to cope with anxiety motives, and average weekly drinks.ResultsThe mediation model for the full sample indicated significant indirect effects of SA severity on drinking to cope with anxiety through PTSS, but not on average weekly drinks. Moderation analyses revealed differential relationships between the variables based on both gender identity and sexual orientation. For instance, the association between SA severity and PTSS was stronger for cisgender women and TGD individuals compared to cisgender men, and for LGBQ+ individuals compared to heterosexual individuals. While the association between PTSS and average weekly drinks was only significant for cisgender men, the association between PTSS and drinking to cope with anxiety was significant for both cisgender men and women but not TGD individuals. Further, the association between SA severity and drinking to cope with anxiety was stronger for cisgender women than cisgender men.ConclusionsFindings from the current study demonstrate sexual orientation and gender identity differences and similarities in the associations of SA severity, PTSS, drinking to cope with anxiety, and alcohol use. Results are discussed in relation to the self‐medication hypothesis and tailoring interventions for diverse groups.