Posttraumatic stress symptoms are chronic, debilitating, and unlikely to remit without treatment. Given the significant dysfunction that is often associated with severe PTSD symptoms, investigation of underlying factors that maintain these symptoms is warranted. Previous research indicates that negative affect (NA) is significantly associated with posttraumatic stress symptom severity (Tull, Jakupcak, McFadden, & Roemer, 2007). Given that NA is a broad measure of distress, thought suppression may be a mediating variable that exacerbates this distress. This study will investigate thought suppression as a mediator of the relationship between NA and posttraumatic symptom severity. To examine this relationship, a mediation analysis will be conducted in a sample of 127 college students who have endorsed a past experience of criterion A traumatic event. Significant findings would provide a more comprehensive understanding of specific cognitive processes, like thought suppression, as possible mediators of the relationship between NA and PTSD symptoms. A primary implication of this analysis is that thought suppression may represent a viable treatment target to mitigate both NA intensity and PTSD symptom severity.