The Constitution of the Islamic Republic of Pakistan (Urdu: آئین پاکستان), also known as the 1973 Constitution, is the supreme law of Pakistan. Drafted by the government of Zulfiqar Ali Bhutto, with additional assistance from the country's opposition parties, it was approved by the Parliament on 10 April and ratified on 14 August 1973.

The Constitution is intended to guide Pakistan's law, its political culture, and system. It identifies the state (its physical existence and its borders), people and their fundamental rights, state's constitutional law and orders, and also the constitutional structure and establishment of the institutions and the country's armed forces. The first three chapters establish the rules, mandate, and separate powers of the three branches of the government: a bicameral legislature; an executive branch governed by the Prime Minister as chief executive; and an apex federal judiciary headed by Supreme Court. The Constitution designates the President of Pakistan as a ceremonial Head of State who is to represent the unity of the state. The first six articles of the constitution outline the political system as federal parliamentary republic system; as well as Islam as its state religion. The Constitution also encapsulates provisions stipulating the legal system's compliance with Islamic injunctions contained in the Quran and Sunnah.The Parliament cannot make any laws which may be repugnant or contrary to the Constitution, however the Constitution itself may be amended by a two-thirds majority in both the houses of the bicameral Parliament, unlike the previous legal documents of 1956 and 1962. It has been amended over time, and most recent impulses for political upgrades and reforms has been amended. Although enforced in 1973, Pakistan, however, celebrates the adoption of the constitution on 23 March—when the first set was promulgated in 1956—each and every year as Republic Day.

Technically there are 26 amendments but 23 amendments were made in constitution and three were not passed by the parliament.