Following exposure to a potentially traumatic event (PTE), some individuals experience negative mental health outcomes such as posttraumatic stress disorder (PTSD), depression, and anxiety. Substance-involved trauma-substance use that occurs immediately before or during a PTE-may confer a unique risk for these complications. Yet, current research on the role of substance use in response to PTEs is sparse, and the existing literature has focused predominantly on alcohol-involved sexual assault. The present study examined associations among substance-involved trauma and poorer mental health functioning with the following aims: (a) descriptively characterize substance-involved trauma in a college sample and (b) examine the effect of substance-involved trauma on PTSD, depression, and anxiety symptoms. Trauma-exposed college students (N = 194) completed a structured clinical interview and self-report questionnaires. Findings revealed that 43% of the sample reported exposure to at least one substance-involved traumatic event in their lifetime. Notably, 86% of traumas were interpersonal (e.g., sexual trauma, physical assault). A history of substanceinvolved trauma was associated with heavier and more problematic drinking, more severe PTSD and anxiety symptoms, but not more severe depressive symptoms, compared to those without substance-involved trauma. Results of this study suggest that substance involvement during trauma is prevalent and contributes to harmful psychological and behavioral outcomes. These findings point to the potential value of eliciting information on substance use proximal to PTE exposure and incorporating this information into individualized treatment plans to enhance clinical care efforts. Future research should assess and include information about substance use in PTEs when modeling trauma outcomes.