Purpose/Objective: To (a) examine the factor structure of the original 47-item Caregiver Appraisal Scale (CAS) in caregivers of service members/veterans (SMVs) following traumatic brain injury (TBI) and (b) assess whether the CAS yields a similar factor structure in this population compared to caregivers of civilian adults following TBI. Research Method/Design: Participants were 287 caregivers (female = 96.2%; spouse = 87.8%; mean age = 38.6 years) of SMVs who sustained a mild, moderate, severe, or penetrating TBI, recruited from Walter Reed National Military Medical Center and via caregiver community outreach. Caregivers completed the CAS, Caregiver Questionnaire, and Mayo-Portland Adaptability Inventory–4 upon enrollment in the study. Results: Principal component analysis (PCA) revealed four factors that explained 43.2% of the variance in CAS scores: Perceived Burden, Caregiving Relationship Satisfaction, Caregiving Ideology, and Caregiving Mastery. Thirty-seven of the 47 CAS items loaded significantly onto only one of the four factors (≥ .40). A secondary PCA was performed on these 37 items, resulting in a four-factor solution very similar to that of the 47-item solution, which explained 46.8% of the variance in the 37-item measure. All but one item loaded significantly on a factor corresponding to a conceptually similar construct. Conclusions/Implications: Military and civilian caregivers have overlapping and differing concerns. The findings support a 37-item four-factor model of caregiving stress appraisal that has the potential for use as an outcome measure for developing caregiver interventions. It may be as useful to administer a reduced 37-item measure of the CAS to caregivers as the original 47-item measure, but further development is required. (PsycINFO Database Record (c) 2019 APA, all rights reserved)