Trauma-focused psychotherapies can be effectively delivered using a massed delivery format. Telehealth treatment for posttraumatic stress disorder (PTSD) using evidence-based interventions has been shown to be as effective as in-person treatment. However, the effectiveness of evidence-based treatments for PTSD over telehealth using the massed delivery format requires further examination. To examine the effectiveness of telehealth massed PTSD treatment, we report on a quality improvement study of 33 veterans (75.8% male; MAge = 42.3, SD = 11.0) who participated in a virtual 4-week massed PTSD program at a Department of Veterans Affairs (VA) medical center. Twenty-seven (81.8%) veterans completed the treatment and reported large reductions in PTSD (d = 1.48) and depressive symptoms (d = 1.08) at Week 4 and at 1-month follow-up (PTSD, d = 1.34; depression, d = 0.70). Results suggested that evidence-based treatment for PTSD can be effectively delivered in a massed format over telehealth in a VA medical setting. (PsycInfo Database Record (c) 2024 APA, all rights reserved).