Research has indicated a link between the moral circle and an individual’s prosocial behaviour. However, it remains uncertain whether this relationship holds across a broader range of countries and is influenced by sociocultural contexts. Drawing from an international dataset encompassing 49,540 participants from 57 countries, this study examined the impact of the moral circle on an individual’s generosity and the moderating role of cultural religiosity. The results revealed a significant positive association between moral circle and generosity in a cross-national context. Notably, in religious cultures, the connection between the moral circle and generosity was found to be weaker. Three robustness checks further affirmed that these findings are robust. The research confirmed a positive relationship between the moral circle and generosity in a multinational context but also highlighted the moderating role of cultural religiosity. This finding suggested that future research should further investigate how cultural and religious frameworks influence ethical behaviour.