Purpose: Family disruption is often an indirect consequence of providing care for a person with traumatic brain injury (TBI). This article describes the development and preliminary validation of a Family Disruption scale designed for inclusion within the TBI-CareQOL, measurement system. Method/Design: Five hundred thirty-four caregivers of persons with TBI (service member/veteran n = 316; civilian n = 218) completed the Family Disruption scale, alongside several other measures of caregiver strain and health-related quality of life. Classical test theory and item response theory (IRT)-based analyses were conducted to develop, and establish reliability and validity of, this scale. Results: Exploratory and confirmatory factor analysis, as well as Samejima's graded response model-related IRT fit analyses. supported the development of a 3-item scale. This final scale is scored on a T score metric (M = 50; SD = 10); higher scores are indicative of more family disruption. Reliability (internal consistency; test-retest stability) was supported for both caregiver groups, and average administration times were under 10 s. Convergent and discriminant validity were supported by strong correlations between Family Disruption and measures of caregiver burden, and smaller correlations with positive aspects of caregiving. As evidence of known-groups validity, caregivers of lower-functioning persons with TBI experienced more family disruption than caregivers of higher functioning individuals. Conclusions: The TBI-CareQOL Family Disruption scale is a brief, reliable, and valid assessment of caregiver perceptions of how caring for an individual with a TBI interferes with family life. This measure is well-suited for inclusion in studies seeking to support family functioning in persons with TBI.