Apart from very small countries such as Singapore and Bahrain, Bangladesh is the most densely populated country in the world. The nation, at 912 persons per square km, has often been compared to Indonesia's Java.

Bangladesh is ethnically homogenous, with Bengalis comprising 98% of the population. The vast majority speak Bengali or Bangla. The remaining two percent are Urdu-speaking, non-Bengali Muslims from other regions of India such as Bihar. A small number of tribal groups inhabit the Chittagong Hill Tracts in the southeast.

Most Bangladeshis (about 83%) are Muslims, but Hindus constitute a sizable (16%) minority. There are also a small number of Buddhists, Christians, and Animists. Bengali, a member of the Indo-Aryan languages is written in a script similar to Devanagari. It is the official language, though English is accepted in official tasks and in (higher) education.

Many minority groups face severe persecution for their ethnicity and religion. The government has yet been able to control the situation.

Bangladesh is plagued by overpopulation. In 1992, the government began promoting birth control to slow growth, but with limited success. Many are landless or forced to inhabit hazardous flood-plains, with the consequence of rampant water-borne disease. In an effort to stem the spread of pathogens like cholera and dysentery, international organizations began to promote well-drilling throughout the nation. Several years after wide-spread implementation of the programme, over a quarter of the population exhibited symptoms of arsenic poisoning. High levels of naturally occuring arsenic in the water table had not been accounted for. The effects of arsenic-tained water still remain a problem.