Although Written Exposure Therapy (WET) is listed in the upcoming VA/DoD PTSD Practice Guidelines as an evidence-based, recommended PTSD treatment, there are limited data supporting the use of WET with veterans suffering from PTSD. Additional research is needed to support the use of WET for the treatment of veterans diagnosed with PTSD. The goal of this study is to investigate whether WET is non-inferior in the treatment of PTSD in a sample of veterans diagnosed with PTSD. Men and women veterans diagnosed with PTSD will be randomly assigned to either WET (n = 75) or Prolonged Exposure (PE; n = 75). PTSD symptom severity will serve as the primary outcome. Assessments will be conducted by independent evaluators at baseline, 10-, 20-, and 20-week post first treatment session. WET is expected to be non-inferior to PE in reducing PTSD symptom severity. In addition, WET is expected to have significantly lower treatment dropout rate relative to the first five sessions of PE (i.e., better treatment engagement). Moderators of treatment outcome for both treatment conditions will also be investigated. If WET is found to be non-inferior to the more time intensive PE treatment then the VA will have evidence to support the use of a brief PTSD treatment, which will assist in addressing the high demand for PTSD clinical services.