This study deciphers the historical trajectory of Buddhism in Bangladesh, focusing on its decline following the Pala Empire and its revival under British colonial rule. Based on epigraphic, literary and archaeological evidence, it points to a convergence of factors—state-run persecution, a withdrawal of royal patronage, the ascendancy of Brahmanical orthodoxy, religious atrocities and the influence of Tantric forms of worship—that resulted in the decline of Buddhist institutions and doctrinal rigour. The paper draws attention to, and documents instances of, the survival of Buddhist Practices in the Chittagong and Chittagong Hill Tract areas; isolation and cultural links with Arakan supporting continuity. The colonial period offered a fertile ground for revival through the influence of Arakanese refugees, transregional monastic networks, and reformist figures like Saramedha Mahathera and Queen Kalindi. Through institutional reforms, laymonastic cooperation, and the adoption of Theravada principles, a distinct Buddhist identity was reasserted. Hence, this work contributes to understanding how religious traditions regenerate amidst persecution, displacement, and cultural syncretism.