question: BACKGROUND: Mild traumatic brain injury (mTBI) is a signature wound of Veterans of operations in Iraq and Afghanistan (i.e., OIF/OEF/OND). Most Veterans with mTBI also experience stress-based psychopathology (e.g., depression, posttraumatic stress disorder) and chronic pain. This combination - referred to as polytrauma - results in detrimental long-term effects on social, occupational, and community reintegration. This study will compare the efficacy of a one-day Acceptance and Commitment Training plus Education, Resources, and Support (ACT+ERS) workshop to a one-day active control group (ERS) on symptoms of distress and social, occupational, and community reintegration. We will also examine mediators and moderators of treatment response. METHODS: This is an ongoing randomized clinical trial. 212 OIF/OEF/OND Veterans with polytrauma are being recruited. Veterans are randomly assigned to a one-day ACT+ERS or a one-day ERS workshop with two individualized booster sessions approximately two- and four-weeks post-workshop. Veterans complete assessments prior to the workshop and again at six weeks, three months, and six months post-workshop. Of note, workshops were converted to a virtual format due to the COVID-19 pandemic. RESULTS: The primary outcomes are symptoms of distress and reintegration; secondary outcomes are post-traumatic stress disorder symptoms and pain interference. Secondary analyses will assess whether changes in avoidance at three months mediate changes in distress and reintegration at six months. CONCLUSION: Facilitating the psychological adjustment and reintegration of Veterans with polytrauma is critical. The results of this study will provide important information about the impact of a brief intervention for Veterans with these concerns.