Constitution of the People's Republic of Bangladesh was adopted by the Constituent Assembly on 4 November 1972 and came into force on 16 December of the same year, marking the Victory Day. The Constitution has 153 Articles arranged under eleven parts and 4 schedules entitled the Republic, Fundamental Principles of State Policy, Fundamental Rights, the Executive, Prime Minister and the Cabinet, the Legislature, Legislative and Financial Procedure, Ordinance Making Power, Judiciary, Elections, Comptroller and Auditor General, Services of Bangladesh, Public Service Commission, Emergency Provisions, Amendment of the Constitution, and Miscellaneous.

The Constitution has declared Bangladesh a Republic committed to the principles of democracy and human rights; rule of law; freedom of movement, assembly and association; freedom of religion and international peace and harmony. Since 1972, the Constitution has undergone certain amendments and changes, some by way of constitutional amendments and some under Martial Law Proclamation Orders. The form of government has also undergone changes quite a number of times. Bangladesh began its constitutional journey with an ad hoc constitution under the Proclamation of Independence Order (10 April 1971) investing the president (of the mujibnagar government) with all executive and legislative authority and the power to appoint a prime minister. This proclamation order was replaced by the Provisional Constitution of Bangladesh Order, 1972 which declared the members elected to the National Assembly and Provincial Assemblies of Pakistan in the elections held in December 1970 and March 1971 as the Constituent Assembly of the Republic. The Order changed the form of government to a parliamentary system with a cabinet of ministers headed by the Prime Minister.

The Constitution was fundamentally amended in January 1975. Under the Constitution (Fourth Amendment) Bill 1975, the parliamentary system was abandoned and a one-party presidential system introduced. From 15 August 1975 to 9 April 1979, there were several rounds of martial laws interspersed with civil governments. The governments, civil or military, during the period had neither abrogated the Constitution nor observed it fully. Every regime ruled partly by decrees, partly by Constitution. All the constitutional anomalies were regularised and confirmed under the Constitution (Fifth Amendment) Act, 1979. Under this amendment all Proclamations, Martial Law Regulations, Martial Law Orders and other laws and tribunals made during the period from 15 August 1975 to 9 April 1979 were ratified and confirmed. The subsequent Martial Law Proclamation, Chief Martial Law Administrator's Orders, Martial Law Regulations and Ordinances were confirmed and ratified by the Constitution (Seventh Amendment) Act, 1986. The multi-party presidential form of government had continued down to 1991 when the Constitution was again amended in favour of a parliamentary system of government.

Under the Constitution (Twelfth Amendment) Act, 1991, the Prime Minister became the executive head, and the President the constitutional head. The executive power of the Republic, according to the twelfth amendment, shall be exercised by the Prime Minister, and his/her cabinet shall be collectively responsible to the Jatiya Sangsad. However, all executive actions of the government shall be expressed to be taken in the name of the President, though the presidency is vested with practically no executive power. Theoretically, the President has the power to appoint the Prime Minister and the Chief Justice. But such power is formal than actual. The President, like the Crown of Britain, holds dignity and grace, not power. The constitutionally very significant amendment to the Constitution is the Constitution (Thirteenth Amendment) Act, 1996 which provided for a Non-Party caretaker government which shall work during the period from the date on which the Chief Adviser enters office after Parliament is dissolved till the date on which a new Prime Minister enters upon his or her office. The Non-Party Caretaker Government, which is headed by a Chief Advisor, is collectively responsible to the President. Under the Constitution (Fifteenth Amendment) Act 2011, the provision for Caretaker Government has been excluded. [Sirajul Islam]

See also constitutional amendments; constitutional development.