This paper interrogates the crystallization of Deobandi thought within Bangladeshi society, with particular focus on the politics of “protection of Islam.” While the spread of Deoband’s educational movement, especially through the founding of Deobandi-type madrasas, and the emergence of Deobandi Islam as a distinct strand of Islamic thought are historically rooted in the broader South Asian context, the evolution of Deobandi Islam in Bangladesh demands specific contextualization. This paper explores how Deobandi Islam spread across Bangladesh, evolved into a distinct Islamic current, and how its custodians engage in the politics of “protecting Islam” in three key areas: (1) safeguarding the independence of the Qawmi madrasa system from state intervention, (2) promoting “authentic” Islam by resisting and denouncing Sufi-saint based veneration, and (3) upholding a normative Islamic moral order in public life. In light of what has been described as the “failure of Islamism,” this paper argues that the politics of “protection of Islam” marks a shift in Deobandis reformist activism—from a “privatized” and “interiorized” movement to one that is increasingly “de-privatized” and “outward-facing,” as Ingram (2018) has aptly noted. This outward orientation seeks to Islamize both the Bangladeshi state and society in interaction with other Islamic and Islamist forces.