The Constitution, as the highest legal document, determines the framework of power and legitimacy, and its revision enables adaptation to social developments. This research, using a qualitative approach and analytical-comparative method, conducts a comparative review of the revision structure in Iran's two constitutions—the Constitutional Era (1906) and the Islamic Republic (1979 and the 1989 amendment)—and evaluates its relationship with popular sovereignty, emphasizing constitutionalist teachings.Findings show that the 1906 Constitution initially lacked any explicit revision mechanism; a silence rooted in the fear of reproducing tyranny, which created legal rigidity. This gap was partially filled in 1949 and 1957 with the establishment of the Constituent Assembly. In contrast, the 1979 Constitution, through Article 177, provides a specific revision mechanism, which was added during the 1989 revision. Both systems maintain a core of immutable principles. The main conclusion is that the revision structure in Iran, in both periods, faces two common structural obstacles: the dominance of an elitist political culture and the lack of institutionalized mechanisms for public dialogue before resorting to popular votes. Consequently, the people's will has appeared not as a constituent power or active partner in producing the revision text, but merely as a final ratifier.