["Journal of Traumatic Stress, EarlyView. ", "\nAbstract\nWritten exposure therapy (WET) has become increasingly recognized alongside other evidence‐based treatments of posttraumatic stress disorder (PTSD), with a rapidly growing evidence base. However, current research has not yet investigated the effect of WET on comorbid depression. We conducted a systematic review to examine the efficacy of WET for comorbid depression among PTSD populations. The primary aim of this review was to investigate WET's effectiveness in reducing depression at posttreatment and follow‐up. A review of five major databases, with no language or publication date restrictions, yielded 18 papers that met all inclusion criteria. Due to variability among studies, including study design, population studied, and modifications to WET, we integrated the current literature descriptively. The individual study findings reported an overall reduction in depressive symptoms, with within‐group effect sizes ranging from small to large, ds = 0.39–1.43. The noninferiority randomized controlled trial included in the review found that WET was comparable to CPT, d = 0.19. These findings suggest that WET may be effective for reducing depressive symptoms in PTSD populations, and future trials should measure and report depression outcomes to contribute to the WET literature.\n"]