A sizeable literature has demonstrated strong negative associations between widowhood and health, but longitudinal evidence on moderating factors has been mixed. This study assesses the roles of pre-existing social capital and wealth in moderating changes in health in the event of spousal death. Samples of widowed individuals (n = 796) and matched married controls (n = 8233) are employed from 17 consecutive waves of the Household, Income and Labour Dynamics in Australia Survey (2001-2017). Individual-level fixed-effects models are used to estimate changes in physical and mental health before and after spousal death, in reference to one's own health more than two years before widowhood. Results show a temporary physical health improvement in the year of spousal death, and a decline in mental health beginning up to two years before spousal death, lasting up to two years after spousal death. Using social capital-from children, club membership or volunteering status, and social connections-observed earlier than two years before spousal death, this study finds that widowed individuals with higher social capital show poorer mental health than those with less capital. This negative moderating role is more marked among widowed males than females. In contrast, greater wealth, particularly from non-financial assets, is associated with earlier psychological adjustment among males. For females, mental health in widowhood shows little difference by wealth. These findings suggest that social capital may not be sufficient to protect deteriorations in mental health among widowed individuals, and that the pursuit of alternative avenues may be especially important among the less wealthy.