The area which is now Bangladesh has a rich historical and cultural past, combining Dravidian, Indo-Aryan, Mongol/Mughul, Arab, Persian, Turkic, and west European cultures. Residents of Bangladesh, about 98% of whom are ethnic Bengali and speak Bangla, are called Bangladeshis. Urdu-speaking, non-Bengali Muslims of Indian origin, and various tribal groups, mostly in the Chittagong Hill Tracts, comprise the remainder. Most Bangladeshis (about 88.3%) are Muslims, but Hindus constitute a sizable (10.5%) minority. There also are a small number of Buddhists, Christians, and animists. English is spoken in urban areas and among the educated.

Sufi religious teachers succeeded in converting many Bengalis to Islam, even before the arrival of Muslim armies from the west. About 1200 AD, Muslim invaders established political control over the Bengal region. This political control also encouraged conversion to Islam. Since then, Islam has played a crucial role in the region's history and politics, with a Muslim majority emerging, particularly in the eastern region of Bengal.