In many European countries, including the Netherlands, the healthcare system is financed according to the principles of solidarity. It is important, therefore, that public support for solidarity in healthcare financing is sufficient in order to ensure that people remain willing to contribute towards solidarity-based systems. The high willingness to contribute to the healthcare costs of others in the Netherlands suggests that support is generally high. However, there are differences between groups. Previous research has focused on mechanisms at the individual and institutional level to explain these differences. However, people's social context may also play a role. Little research has been conducted into this. To fill this gap, we examined the role of perceived social support and social norms in order to explain differences in the willingness to contribute to other people's healthcare costs. In November 2021, we conducted a survey study in which a questionnaire was sent to a representative sample of 1,500 members of the Dutch Healthcare Consumer Panel. This was returned by 837 panel members (56% response rate). Using logistic regression analysis, we showed that people who perceive higher levels of social support are more willing to contribute to the healthcare costs of others. We also found that the willingness to contribute is higher when someone's social context is more supportive of healthcare systems that are financed according to the principles of solidarity. This effect does not differ between people who perceive low and high levels of social support. Our results suggest that, next to the individual and institutional level, the social context of people has to be taken into consideration in policy and research addressing support for solidarity in healthcare financing.