As a religion, Islam claims to organize the daily life of Muslims in a detailed way through the rules it has laid down. Unlike pre-modern Muslim scholars, modern academia attributes to this body of rules legal value in a modern sense and calls it “Islamic law.” Nonetheless, except Wael Hallaq's brief discussion, the accuracy of this nomenclature is generally taken for granted. This paper seeks to understand whether the body of rules laid down by Islam can indeed be considered law. In doing so, I examine Islamic law through the lens of one of the most influential legal theorists of all times, H. L. A. Hart. In his pathbreaking work, The Concept of Law, Hart has claimed that his understanding of law is “a union of primary rules of obligation with ... secondary rules,” and his theory is “not tied to any particular legal system or legal culture” but rather general and applicable to all contexts. To assess whether Islamic law can be considered law, I examine Islamic legal tradition through the lens of The Concept of Law and explore to what extent Hart’s theoretical understanding is applicable to Islamic law. I argue that Hart’s theory of law is not applicable to and can hardly be reconciled with so-called “Islamic law.” While Hart has built his theory as a union of primary and secondary rules (i.e., the rules of adjudication, rules of change, and rules of recognition), the latter has little to no relevance in Islamic legal tradition. Instead, secondary rules are both unbeknownst to and meaningless for Muslim jurists. This leads to the conclusion that either Islamic law fails to meet Hart’s criteria to qualify as law or, vice versa, Hart’s concept of law fails to comprehend Islamic law, depending on which standpoint would be taken.