Although most posttraumatic stress disorder (PTSD) care in the Veterans health administration (VHA) is provided on an outpatient basis, the VHA has 40 residential rehabilitation treatment programs (RRTPs) designed to treat Veterans who require more intensive and closely monitored care. Unfortunately, the clinical outcomes of these programs are modest, and previous attempts to identify key drivers of outcomes have uncovered few modifiable factors. The present study, informed by the model of resources, life events and changes in psychological state, was designed to identify factors associated with treatment response among RRTP patients and providers. Semistructured interviews were conducted with 24 patients and 12 providers at three regional RRTPs, using interview guides based on the theoretical model. Data were analyzed using rapid analysis. Results showed that patients and providers agreed on several factors critical to RRTP success. These factors included the provision of evidence-based psychotherapy (EBP), support and understanding from fellow patients, and skill and support from providers. Patients and providers also noted the importance of psychological flexibility, openness, and willingness to change. Patients who experienced less symptom improvement over the course of treatment were more likely to report poor therapeutic alliance. These findings underscore the importance of continued emphasis on EBP delivery but also suggest that RRTPs might find additional ways to capitalize on the residential milieu to encourage engagement in treatment and a focus on therapeutic change. (PsycInfo Database Record (c) 2022 APA, all rights reserved).