Interest in political secularism is growing, due to its proven relevant role in affecting people’s political behaviours and attitudes toward human rights. However, until now, only a few studies have analysed its influence on religious freedom and those which exist do so mostly from a governmental-policy perspective. Drawing upon the sociology of religious freedom, this article seeks to address this gap. Comparing two Catholic EU countries, Italy and Croatia, and adopting an empirical perspective, it aims to understand whether the endorsement of political secularism enhances or limits support for religious freedom. More specifically, the study draws a key distinction between two models of secularism, ‘institutional’ and ‘ideological’, whose impacts on different aspects of religious freedom are assessed. In doing so, this research presents the results of a cross-national survey on Social Perception of Religious Freedom (SPRF) that was carried out among university students in Italy (=714) and Croatia (=603). The results show the strong positive influence of moderate forms of political secularism in shaping a positive culture of religious freedom. At the same time, they validate the hypothesis that it is necessary to consider political secularism’s multiple facets to fully understand its influence on support for religious freedom in different countries.