Objective The purpose of this study was to use actor–partner interdependence modeling (APIM) to examine the simultaneous effects of both acquired brain injury (ABI) patient and caregiver ratings of patient impairments on both patient and caregiver ratings of caregiver psychosocial dysfunction. Method A sample of 968 individuals with ABI and their caregivers (n = 1,936) from 4 countries completed the European Brain Injury Questionnaire, a measure of ABI impairments and caregiver psychosocial functioning in the context of providing care for the person with ABI. Results An APIM with all adequate or good fit indices found that patient ratings of their own impairments in the domains of social disadaptation and depression were uniquely and positively associated with patient ratings of caregiver psychosocial dysfunction, yet none of the patient ratings of their own impairments were uniquely associated with caregiver ratings of caregiver psychosocial dysfunction. Caregiver ratings of patient impairments across all 3 domains (cognition, social disadaptation, and depression) were uniquely and positively associated with caregiver ratings of caregiver psychosocial dysfunction. Yet only caregiver ratings of patient social disadaptation were uniquely and positively associated with patient ratings of caregiver psychosocial dysfunction. Conclusions These findings suggest that caregivers’ views of ABI patients’ impairments are likely much more associated with caregiver psychosocial functioning than are patients’ views of their own impairments, pointing to caregivers’ interpretations of their patients’ impairments as a primary target for cognitive behavioral interventions.