The purpose of this paper is to explore and conceptualize the mechanism of Islamization that is specific to Bangladesh, focusing on the cases of some villages in Tangail district. First, this paper reviews the theories and process of Islamization worldwide and in the case of Bangladesh. This review leads the hypothesis that the deepening of Islamic knowledge and practice in rural Bangladesh has been caused by the spread of modern religious education and Bangladeshi travelers to the Middle East, particularly Saudi Arabia, as pilgrims and migrant workers. Second, changes in daily practice and religious activities along with the Islamization of the population and the landscape as well as socio-economic changes are described. Third, this paper explores the source of local people’s Islamic learning, the changes in religious education, and social and cultural impacts of travelers to the Middle East on local society. The significant triggers of the spread of Islamic knowledge are the achievement of a certain degree of economic status, modern Islamic education, and work by Islamic intellectuals including those who returned from Saudi Arabia. Finally, this paper provides a model of Islamization with the use of the concept of “Islamic locale” and examines the mechanism of Islamization that is specific to Bangladesh and its connections, as well as the similarities with and differences from Islamic revivalism worldwide.