“This chapter discusses some of the different forms of religiosity in Kurdistan over the centuries. Countering a longstanding bias in favour of minorities and heterodox groups, like Christians, Jews, Yezidis and Alevis, it also explores whether one may find more orthodox forms of Islam that are specific to the Kurds, or to the region predominantly inhabited by Kurds. Accordingly, it focuses on the emergence of vernacular religious learning in Kurdish in early modern times, and on the spread of the Khalidiyya branch of the Naqshbandî Sufism during the Tanzimat period and after. From a historical, and genealogical, perspective, it emerges that questions of orthodoxy and heterodoxy have witnessed qualitative changes over the centuries, reflecting changing forms and modalities of power; from a global-historical perspective, it appears that new articulations of religious orthodoxy in the nineteenth-century Ottoman Empire, in particular the rise of the Khalidiyya Naqshbandî tarîqa, reflect, and interact with, wider developments, like the centralization of state power, the emergence of Wahhabism and the arrival of Christian missionaries. Finally, it discusses the qualitative religious changes accompanying the rise of post-Ottoman nation-states and their epiphenomena, up to and including, most notoriously, the so-called Islamic State.”