We seek to explain variation in the descriptive representation of Muslim minorities in national legislatures, relying on an original data set that includes 635 seats filled by Muslim-origin MPs in the lower chambers of national parliaments of twenty-six European polities in three legislative cycles between 2007 and 2018. We argue that the image of a polity as a union of multiple ethnocultural groups, reflected in concrete state policies and institutional arrangements, may be conducive to better descriptive representation of Muslim minorities, who were not originally envisioned as one of the communities constituting the nation. The results of multivariate regression analysis provide support for our hypothesis that the extent to which ethnocultural diversity is recognized and institutionalized helps explain variation in the levels of descriptive representation of European Muslims. We supplement our findings with congruence testing in four brief case studies: Belgium, France, the Netherlands, and Bulgaria.