This study used a modern theory of stress as a framework to strengthen the understanding of the relationship between neurobehavioural problems of TBI, family functioning and psychological distress in spouse/caregivers. The research was an ex post facto design utilising a cross-sectional methodology. Path analysis was used to determine the structural effect of neurobehavioural problems on family functioning and psychological distress. Forty-seven female and 17 male spouse/caregivers of partners with severe TBI were recruited. Spouse/caregivers who reported partners with TBI as having high levels of behavioural and cognitive problems experienced high levels of unhealthy family functioning. High levels of unhealthy family functioning were related to high levels of distress in spouse/caregivers, as family functioning had a moderate influence on psychological distress. Furthermore, indirect effects of behavioural and cognitive problems operating through family functioning intensified the level of psychological distress experienced by spouse/caregivers. Additionally, spouse/caregivers who reported high levels of behavioural, communication and social problems in their partners also experienced high levels of psychological distress. This study was significant because the impact of TBI on the spouse/caregiver from a multidimensional perspective is an important and under-researched area in the brain injury and disability field.