The majālis (sermons) of the Fāṭimī Dāʿī, al-Muʾayyad al-Shīrāzī, held in the 11th century CE/ 5th century AH, hold a significant place in representing the theological concepts validated by the Fāṭimī imam-caliphs, who ruled in North Africa, Egypt and parts of the Arab world for more than two centuries. One of those fundamental theological concepts explained by al-Muʾayyad al-Shīrāzī is the notion of iʿjāz al-Qurʾān (inimitability of the Qur’an), a doctrine that has been one of the primary areas of debate in Islamic theological discussions since that period up until modern times, especially in the genre of literature associated with “signs of prophethood”. What does the miracle of the Qur’an subsist in? Was the Qur’an a muʿjiza (miracle) only for the Arabs? If the Arabs did not know what they were being challenged then would the Quranic challenge to reproduce a similar Qur’an would even be a valid one? What was distinctive about al-Dāʿī al-Muʾayyad’s explanation of this doctrine in the contemporary discourse of his time? This paper shall focus on the arguments provided by al-Dāʿī al-Muʾayyad that on one side explicitly and implicitly manifested itself in the Shīʿī-Ismāʿīlī intellectual history surrounding the notion of Imamate, and on the other side when juxtaposed with other contemporary interpretations, provided a framework to understand the distinctive characteristic of the Fāṭimī-Ismāʿīlī discourse in this context. In elucidating the concept of iʿjāz al-Qurʾān, the majālis of al-Muʾayyad al-Shīrāzī’, in the paradigm of Fāṭimī-Ismāʿīlī traditions, illustrate a variety of intricate themes that embody a certain characteristic of mutually harmonizing religious belief with rationality, without compromising its foundational principles.