Abstract: OBJECTIVE: We sought to examine changes in mild-to-moderate TBI-related symptoms among service members and veterans (SM/Vs) following participation in a 5-site inpatient rehabilitation program with the US Department of Veterans Affairs between 7/1/2022 and 5/30/2024. METHODS: Neurobehavioral outcomes, posttraumatic stress disorder (PTSD) symptoms, pain interference, and lifestyle behaviors related to brain injury were assessed at baseline, discharge, and a 6-month follow-up. Mixed effects linear regression models, adjusting for key patient characteristics, were estimated to determine changes in TBI-related outcomes across the 3 time points. RESULTS: Mean participant age, for those with complete data (n = 127), was 41.64 years (SD = 5.57), with a mean of 7.45 deployments (SD = 3.12) and 16.32 concussive events (SD = 7.21). Participants were predominantly White (73.23%) Special Operations personnel (82.68%). TBI-related outcomes, including neurobehavioral symptoms, pain interference, PTSD, and brain injury adaptability, decreased significantly from baseline to discharge (b = -14.36, SE = 1.03; b = -3.79, SE = 0.49; b = -11.14, SE = 1.27; b = -2.41, SE = 0.41), with Cohen's d effect sizes of 1.14, 0.71, 0.69, and 0.56, respectively. Six-month follow-up, TBI-related outcomes remained statistically and practically below baseline levels in all measures except adaptability. CONCLUSIONS AND RELEVANCE: Findings illustrate an interdisciplinary, inpatient rehabilitation program for mild-to-moderate TBI yields significant improvements in TBI-related symptoms that are common among SM/Vs and are sustained at 6 months postdischarge.