Traumatic brain injuries (TBI) are injuries that cause physical damage to the brain tissue. But are there other consequences to a TBI? Does the injury extend beyond just simply damage to the brain tissue? We researched the link between TBI and posttraumatic stress disorder (PTSD) in veterans. We performed a meta-analysis using 10 studies found through PyscINFO. The overall effect size between TBI and PTSD is Cohen’s d = 1.02, which indicates a very large effect. We found that a veteran who has a traumatic brain injury is 3.45 times more likely to develop PTSD then a veteran who does not have a TBI. This finding provides insight for all military personnel, as well as mental health care providers. Knowing this relationship is so strong, we can begin earlier monitoring and treating symptoms of PTSD in veterans who have TBI.