Objective: Receipt of concurrent psychotropic prescription medications from both US Department of Veterans Affairs (VA) and non-VA healthcare providers may increase risk of adverse opioid-related outcomes among veterans with traumatic brain injury (TBI). Little is known about patterns of dual-system opioid or sedative-hypnotic prescription receipt in this population. We estimated the prevalence and patterns of, and risk factors for, VA/ non-VA prescription overlap among post-9/11 veterans with TBI receiving opioids from VA providers in Oregon. Setting: Oregon VA and non-VA outpatient care. Participants: Post-9/11 veterans in Oregon with TBI who received an opioid prescription from VA providers between the years of 2014 and 2019. Design: Historical cohort study. Main Measures: Prescription overlap of VA opioids and non-VA opioids or sedative-hypnotics; proportions of veterans who received VA or non-VA opioid, benzodiazepine, and nonbenzodiazepine sedative-hypnotic prescriptions were also examined by year and by veteran characteristics. Results: Among 1036 veterans with TBI receiving opioids from the VA, 210 (20.3%) received an overlapping opioid prescription from a non-VA provider; 5.3% received overlapping benzodiazepines; and none received overlapping nonbenzodiazepine sedative-hypnotics. Proportions of veterans with prescription overlap tended to decrease over time. Veterans with other than urban versus urban addresses (OR = 1.4; 95% CI, 1.0-1.8), high versus medium average annual VA visits (OR = 1.7; 95% CI, 1.1-2.6), and VA service connection of 50% or more versus none/0% to 40% (OR = 4.3; 95% CI, 1.3-14.0) were more likely to have concurrent VA/non-VA prescriptions in bivariable analyses; other than urban remained associated with overlap in multivariable models. Similarly, veterans with comorbid posttraumatic stress disorder diagnoses were more likely to have concurrent VA/non-VA prescriptions in both bivariable and multivariable (OR = 2.1; 95% CI, 1.0-4.1) models. Conclusion: Among post-9/11 veterans with TBI receiving VA opioids, a considerable proportion had overlapping non-VA prescription medications. Providers and healthcare systems should consider all sources of psychotropic prescriptions, and risk factors for overlapping medications, to help mitigate potentially unsafe medication use among veterans with TBI. Key words: analgesics, benzodiazepines/ * therapeutic use, brain injuries, drug overdose/epidemiology, drug prescriptions/statistics and numerical data, dual use, Iraq War, 2003-2011 safety, opioid/ * therapeutic use, traumatic, VA healthcare system, veterans/ * statistics and numerical data