The paper explores the interaction between religion and citizenship in liberal democracies with secular traditions through the prism of the concept of citizenship within its formal and substantive dimensions. Introducing this dichotomy, we argue that examining the two dimensions separately will contribute to a clearer assessment of the implications of laws and practices that ultimately restrict citizenship – in its global understanding – based on religious belonging. We consider debates of secularism, neutrality and rights while moving beyond them and looking at these practices through the prism of citizenship scholarship across academic disciplines. Applying this framework on examples comparatively across jurisdictions, we show that religion plays a role both in acquiring and exercising the rights and duties of citizenship. In certain instances such role challenges the egalitarian character of the liberal constitutional state.