<p>The demanding tasks of caregiving can lead to stress for caregivers, harming their physical, psychological, and social well-being. We investigated the association between informal caregiving and caregivers’ subjective, affective, and financial well-being in Australia. We have employed the ‘Theory of Caregiver Stress’ to understand caregiver burden from a theoretical lens. We used data from fifteen waves (waves 6 through 20) of the Household, Income and Labour Dynamics in Australia (HILDA) Survey. We constructed an unbalanced panel consisting of 192,104 person-year observations from 26,666 unique individuals. We fitted both fixed-effects ordered logistic regression model (subjective and financial well-being) and fixed-effects GLS regression model (affective well-being) to estimate the association between informal caregiving and caregivers’ well-being according to the type of dependent variable. Moderate (− 0.09 points) and intensive caregiving (− 0.39 points) were significantly associated with a reduction in caregivers’ subjective well-being. Moderate (− 0.77 points) and intensive caregiving (− 2.09 points) were associated with reduced affective well-being. Light (− 0.07 points), moderate (− 0.11 points), and intensive caregiving (− 0.14 points) were also negatively associated with financial well-being. Our analysis provided evidence that adverse and positive life events (contextual stimuli) have a significant association with caregivers’ well-being. A higher caregiver burden (focal stimuli) was associated with lower subjective, affective, and financial well-being for informal caregivers in Australia. These findings highlight the association between significant caregiving burden and adverse well-being outcomes for caregivers. This underscores the need for increased government support for caregivers facing a heavy carer load to potentially reduce the negative association between caring and carer well-being.</p>