Islam is the largest and the state religion of the People's Republic of Bangladesh. According to the 2022 census, Bangladesh had a population of about 150 million Muslims, or 91.04% of its total population of 165 million. Muslims of Bangladesh are predominant native Bengali Muslims. The majority of Bangladeshis are Sunni, and follow the Hanafi school of thought and Fiqh. Bangladesh is a de facto secular country and state.
The Bengal region was a supreme power of the medieval Islamic East. In the late 7th century, Muslims from Arabia established commercial as well as religious connection within the Bengal region before the conquest, mainly through the coastal regions as traders and primarily via the ports of Chittagong. In the early 13th century, Muhammad bin Bakhtiyar Khalji conquered Western and part of Northern Bengal and established the first Muslim kingdom in Bengal. During the 13th century, Sufi missionaries, mystics and saints began to preach Islam in villages. The Islamic Bengal Sultanate was founded by Shamsuddin Ilyas Shah who united Bengal on an ethno-linguistic platform. Bengal reached in her golden age during Bengal Sultanate's prosperous ruling period. Subsequently, Bengal viceroy Muhammad Azam Shah assumed the imperial throne. Mughal Bengal became increasingly independent under the Nawabs of Bengal in the 18th century.