ObjectiveTo examine the relationship between caregiver competence and health-related quality of life (HRQoL) among family caregivers of disabled elderly adults, and to evaluate the role of caregiver burden as a potential mediator of that relationship.DesignCross-sectional study.SettingTwo general hospitals in Shanghai, China.ParticipantsStudy participants were 135 family caregivers of disabled elderly adults listed on a roster for outpatient and emergency services utilisation from January to March 2022.Data analysis and outcome measuresWe used stratified linear regression and structural equation model analysis. HRQoL was the main outcome, measured using the Medical Outcomes Study 36-Item Short form Health Survey. Caregiver competence was assessed using the Family Caregiver Task Inventory, and caregiver burden was assessed with the Zarit Burden Interview.ResultsCaregivers of moderately and severely disabled elderly adults showed poorer scores in Physical Component Summary (F=20.463, p<0.05) and Mental Component Summary (F=17.062, p<0.05) compared with caregivers of older adults with mild disabilities. At the same time, those caregivers showed higher scores on the caregiving burden (F=19.533, p<0.05) and caregiving difficulties (F=16.079, p<0.05). A structural equation model was performed and successfully adjusted (χ2/df=1.175, p=0.261, NFI=0.970, RFI=0.949, IFI=0.995, CFI=0.995, GFI=0.963, TLI=0.992, AGFI=0.920, RMSEA=0.036). The total effect of Family Caregiver Task Inventory scores on HRQoL scores was −0.980, with a direct effect of −0.645. The mediating effect on HRQoL scores through the intermediate variable of caregiver burden scores was −0.335.ConclusionsFamily caregivers’ HRQoL is closely related to caregiver difficulties and burdens. Early identification and targeted measures are needed to reduce the burden and problems in caregiving.