The traditional Iranian state experienced decline and decay during the late Qajar period, and its continuity was not possible. After that, the institution of state underwent transformations throughout various historical periods, and this process continued until the Islamic Republic era. The main question in this article is what are the institutional foundations of the state in the Islamic Republic of Iran? Our hypothesis, based on the historical institutionalism approach, is that the institutional foundations of the state in Iran today are influenced by the institutional heritage of the traditional state ment, the institutional transformation of the state in the critical juncture of the constitutional revolution, the dependence on the oil path in the Pahlavi period, and the institutional transformation of the state in the critical juncture of the 1979 revolution. As a result, the state in Iran after the revolution has combined various elements of the traditional state, the constitutional state, and the Islamic state. The elements that have been combined in an incompatible mixture have different epistemological foundations and historical roots, and therefore, have caused internal conflicts within the state structure. In the present study, a novel theoretical configuration called the “Monticore State” was introduced to explain the unique nature of the state in the Islamic Revolution. On this basis, understanding the internal logic of the state, the formation and perpetuation of macro-scale policies in various areas, and, consequently, the pathology of governance in the Islamic Republic requires understanding the Monticore nature of the state, its institutional legacy, and its historical roots.