This article explores the history of “Islamic Society” (al-Mujtamaʿ al-Islāmī), a concept whose widespread usage is paralleled by shallow understandings of its origins. Scholars of premodern Islamic history often use this term to describe the ideas and practices of Muslim communities under Islamic political rule, while historians of the Muslim Brotherhood highlight this leading Islamist movement’s commitment to forming such a collective yet treat the concept as sui generis. This article, in turn, draws on a wide array of Islamic print media published by leading Islamic movements and state institutions in Egypt between 1898 and 1981 to tell a story of how this concept became intellectually viable and politically meaningful in the context of transition from colonial to postcolonial rule in the mid-twentieth century. Building on histories of religious nationalism which trace how religious nationalist visions produce novel understandings of religious identity rather than replicating prior models, the article explores the ways in which identity is linked to particular projects of religious practice. In doing so, it casts light on how religious nationalist projects seek to structure social life through calls to continuity with the past even as they adopt the core assumptions of the nation-state project. Specifically, it argues that, as Muslim thinkers, activists, and scholars navigated the transition from colonial to postcolonial rule, they turned to this concept to articulate dueling conceptions of religious change through state power and social mobilization alike.