The article introduces the concept of “milletic secularism” which invokes the Ottoman millet system to refer to divergent and competing transnational collective identities, loyalties, and frames of reference coexisting within the same nation-state. These identities are conceptualized as resembling the way religious communities functioned under the Ottoman millet system but in a reverse, upended way, as today Muslims are the minority in a pluralist society and secular state governed on the basis of non-Muslim procedures and values symbolically overarched by Orthodox Christianity. Foregrounding the case of Bulgaria, the article highlights the role of the Ottoman legacy vis-à-vis Orthodox Christian heritage for the accommodation of diversity. Milletic secularism draws on the implicit social knowledge that evokes differing antecedents and values underlying the shared identities of Christians and Muslims. Since the 1990s, after half a century dominated by the “secular religion” of Communism, the intersection of religion and politics in Bulgaria is reshaped by the reemergence of religion as a structural force. Milletic secularism has both integrative and emancipatory potential, fostered and challenged today by a variety of factors. Among them, this article foregrounds the increasingly transnational Sunnī Muslim identity and the ongoing re-Islamization in the form of Ḥanafism and Salafism.