Objective: The purpose of this study was to examine perceived sleep-related impairment in caregivers of individuals with traumatic brain injury (TBI). Specifically, we examined the relationship between caregiver-perceived sleep-related impairment and different aspects of health-related quality of life (HRQOL) and explored whether these relationships were moderated by the perceived level of everyday function in the person with TBI. Method: Three hundred forty-one caregivers of individuals with TBI completed surveys to determine whether the association between sleep-related impairment and HRQOL was moderated by caregiver-perceived functional impairment of the person with injury. Participants completed measures from the Patient-Reported Outcomes Measurement Information System and the TBI-CareQOL. These measures were used to examine different aspects of HRQOL: caregiver-specific HRQOL, mental HRQOL, social HRQOL, and fatigue. The Mayo-Portland Adaptability Inventory-4 was used to measure caregiver perceptions of the level of everyday function in the person with injury. Results: Results indicated that caregiver-perceived sleep-related impairment was associated with each of the four HRQOL scores. This relationship was moderated by the caregiver-reported level of everyday function in the person with TBI for both caregiver-specific HRQOL and fatigue but not mental or social HRQOL. For caregiver-specific HRQOL and fatigue, caregiver-perceived sleep-related impairment was associated with worse HRQOL for those caring for individuals with lower perceived levels of everyday function, but not for those caring for individuals with higher levels of everyday function. Conclusions: Interventions to improve caregiver sleep and HRQOL should consider both psychosocial and environmental factors (i.e., factors related to the person with the TBI). (PsycInfo Database Record (c) 2020 APA, all rights reserved).