ObjectivesThe need to improve the sustainability of public health expenditure, in a climate of growing pressure on national budgets, inevitably leads to a discussion about resource rationing, and the extent of society's responsibility for those expenditures. To contribute to this discussion empirically, this study evaluated the willingness of Portuguese respondents to pay for other individuals' healthcare expenditures through out-of-pocket payments. Study designA questionnaire addressed to the general public was developed, with 296 respondents. The survey was divided into three sections: (i) sociodemographic characteristics of the respondents; (ii) health-related habits; and (iii) willingness to pay other individuals' healthcare expenditures and, if so, how much. MethodsLogit and ordered logit models were applied. ResultsRespondents were divided fairly even between those who were willing to pay for other individuals' healthcare expenditures and those who were not. Respondents with health insurance contracts were more willing to contribute, and the contribution value was higher. Having a degree-level education was associated with reduced willingness to pay for other individuals' healthcare expenditures, and reduced probability of paying a larger amount, which may be associated with holding individuals accountable for their choices. Considering self-reported risky behaviours, the respondents who consumed alcohol were more likely to be willing to pay for other individuals' healthcare expenditures, and to a greater extent, whereas smokers were less likely to pay larger amounts. These effects suggest that respondents with different unhealthy behaviours are not equally altruistic. ConclusionsThese findings highlight the need to combine health policy and social beliefs. The respondents seem to be interested to discuss healthcare funding, given that they agreed to reveal their willingness to pay for other individuals' healthcare expenditures. Moreover, respondents' sociodemographic characteristics and health-related behaviours play a role in their willingness to contribute to social well-being through healthcare expenditures. The differences observed denote that no agreement exists regarding the extent of society's responsibility.