Posttraumatic stress disorder (PTSD) occurs at high rates among student veterans and is known to negatively impact educational functioning; however, the unique effects of PTSD are less clear, given that PTSD is highly comorbid with many other conditions that could potentially affect educational functioning. The present study had two objectives: (a) to determine the impact of PTSD symptom severity on educational functioning after accounting for demographic variables, traumatic brain injury, and commonly co-occurring mental health conditions; and (b) to identify which symptom clusters of PTSD have the greatest impact on educational functioning. Educational functioning and other commonly occurring mental health conditions were assessed cross-sectionally among 90 student veterans. Traumatic brain injury and major depressive disorder (MDD) were initially associated with impaired educational functioning; however, after adding PTSD into the final model, only PTSD (β = .44, p < .001) and MDD (β = .31, p = .001) remained associated with educational impairment. Follow-up analyses indicated that the reexperiencing symptom cluster was most strongly associated with impaired educational functioning (β = .28, p = .031). Overall, these results suggest that PTSD symptoms-especially reexperiencing symptoms-may be a driving force behind impaired educational impairment, even after accounting for other commonly co-occurring mental health conditions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).