Aim: Traumatic brain injury (TBI) is a common neurological condition, which can present with a wide range of neuropsychological symptoms. Treating this broad spectrum of symptoms represents a significant medical challenge. In part because of this, there is growing interest in the use of medical cannabis to treat the sequelae of TBI, as medical cannabis has been used to treat multiple associated conditions, such as pain. However, medical cannabis represents a heterogeneous collection of therapies, and relatively little is known about their effectiveness in treating TBI symptoms. The aim of the present study was therefore to assess medical cannabis use in patients with TBI. Methods: In the present study, a retrospective chart review was conducted of patterns of cannabis use and TBI symptoms in individuals who used medical cannabis to treat TBI-related symptoms. All subjects were recruited from a medical cannabis clinic, where cannabis was authorized by physicians, using licensed cannabis products. A total of 53 subjects provided written consent to have their charts reviewed. Results: Neuropsychiatric conditions, including depression, pain, and anxiety were frequent in this group. The most common forms of medical cannabis consumption at intake included smoking, vaping, and oral ingestion. Patients used a combination of high tetrahydrocannabinol (THC)/low cannabidiol (CBD) and low THC/high CBD products, typically 1–3 times per day. Medical cannabis appeared to be relatively well-tolerated in subjects, with few serious side effects. At follow-up, subjects self-reported improvements in TBI symptoms, although these were not statistically significant when assessed using validated questionnaires. Conclusions: Overall findings indicate modest potential benefits of medical cannabis for TBI, but further research will be required to validate these results.