PURPOSE: Traumatic brain injury (TBI) is a leading cause of death and disability among adults in the United States. There is evidence to suggest the peripheral vestibular system is vulnerable to damage in individuals with TBI. However, there are limited prospective studies that describe the type and frequency of vestibular impairment in individuals with chronic moderate-severe TBI (> 6 months postinjury). METHOD: Cervical and ocular vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) were used to assess the function of otolith organ and horizontal semicircular canal (hSCC) pathways in adults with chronic moderate-severe TBI and in noninjured comparison (NC) participants. Self-report questionnaires were administered to participants with TBI to determine prevalence of vestibular symptoms and quality of life associated with those symptoms. RESULTS: Chronic moderate-severe TBI was associated with a greater degree of impairment in otolith organ, rather than hSCC, pathways. About 63% of participants with TBI had abnormal VEMP responses, compared to only 10% with abnormal vHIT responses. The NC group had significantly less abnormal VEMP responses (7%), while none of the NC participants had abnormal vHIT responses. As many as 80% of participants with TBI reported vestibular symptoms, and up to 36% reported that these symptoms negatively affected their quality of life. CONCLUSIONS: Adults with TBI reported vestibular symptoms and decreased quality of life related to those symptoms and had objective evidence of peripheral vestibular impairment. Vestibular testing for adults with chronic TBI who report persistent dizziness and imbalance may serve as a guide for treatment and rehabilitation in these individuals.