Post-concussion syndrome refers to the adverse group of symptoms following a mild traumatic brain injury (mTBI). The Rivermead post-concussion syndrome questionnaire (RPQ) is a common clinical tool for assessing baseline post-concussion syndrome symptomology; however, it is unknown if scores on this questionnaire are associated with future disability. Therefore, the goal of this study was to determine the association between baseline RPQ scores and future disability in older adults with mTBI. This study used a prospective cohort design, using the RPQ to measure baseline post-concussion syndrome symptomatology. Disability at 6 months was measured using the Glasgow Outcome Scale-Extended (GOSE; disability), short-form 12 (SF-12; physical and mental quality of life), and self-reported recovery. Linear and logistic models adjusted for confounding factors were estimated using 200 bootstrapped samples. Individuals with higher levels of baseline symptomatology were more likely to have poor GOSE scores (RR = 2.13, 95% CI [1.51, 2.31]) and self-reported recovery (RR = 2.64, 95% CI [1.31, 8.98]) 6 months later. High levels of baseline symptomatology may be associated with overall disability and individual perceptions of recovery 6 months post-MTBI. While the RPQ is valid in assessing a patient's post-concussive symptoms following mTBI, it may not predict long-term physical or mental health in older adults.