Objective To examine the reliability and validity of Patient-Reported Outcomes Measurement Information System (PROMIS) measures of sleep disturbance and fatigue in traumatic brain injury (TBI) caregivers and to determine the severity of fatigue and sleep disturbance in these caregivers. Design Cross-sectional survey data collected through an online data capture platform. Setting A total of 4 rehabilitation hospitals and Walter Reed National Military Medical Center. Participants Caregivers (N=560) of civilians (n=344) and service member/veterans (SMVs) (n=216) with TBI. Intervention Not applicable. Main Outcome Measures PROMIS sleep and fatigue measures administered as both computerized adaptive tests (CATs) and 4-item short forms (SFs). Results For both samples, floor and ceiling effects for the PROMIS measures were low (<11%), internal consistency was very good (all α≥0.80), and test-retest reliability was acceptable (all r ≥0.70 except for the fatigue CAT in the SMV sample r =0.63). Convergent validity was supported by moderate correlations between the PROMIS and related measures. Discriminant validity was supported by low correlations between PROMIS measures and measures of dissimilar constructs. PROMIS scores indicated significantly worse sleep and fatigue for those caring for someone with high levels versus low levels of impairment. Conclusions Findings support the reliability and validity of the PROMIS CAT and SF measures of sleep disturbance and fatigue in caregivers of civilians and SMVs with TBI. Highlights • The Patient-Reported Outcomes Measurement Information System (PROMIS) sleep and fatigue measures are both reliable and valid. • The PROMIS sleep and fatigue measures are clinically relevant for caregivers. • Caregivers of persons with brain injury have problems with sleep and fatigue.