The Constitution of the Islamic Republic of Pakistan (Urdu: ), 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 Marchwhen the first set was promulgated in 1956each 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 as the three amendments collapsed.

Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's fifth-most populous country, with a population of almost 227 million, and has the world's second-largest Muslim population. Pakistan is the 33rd-largest country by area, spanning 881,913 square kilometres (340,509 square miles). It has a 1,046-kilometre (650-mile) coastline along the Arabian Sea and Gulf of Oman in the south, and is bordered by India to the east, Afghanistan to the west, Iran to the southwest, and China to the northeast. It is separated narrowly from Tajikistan by Afghanistan's Wakhan Corridor in the north, and also shares a maritime border with Oman.

Pakistan is the site of several ancient cultures, including the 8,500-year-old Neolithic site of Mehrgarh in Balochistan, and the Indus Valley Civilisation of the Bronze Age, the most extensive of the civilisations of the Old World. The region that comprises the modern state of Pakistan was the realm of multiple empires and dynasties, including the Achaemenid; briefly that of Alexander the Great; the Seleucid, the Maurya, the Kushan, the Gupta; the Umayyad Caliphate in its southern regions, the Hindu Shahi, the Ghaznavids, the Delhi Sultanate, the Mughals, the Durranis, the Sikh Empire, British East India Company rule, and most recently, the British Indian Empire from 1858 to 1947.

Spurred by the Pakistan Movement, which sought a homeland for the Muslims of British India, and election victories in 1946 by the All-India Muslim League, Pakistan gained independence in 1947 after the Partition of the British Indian Empire, which awarded separate statehood to its Muslim-majority regions and was accompanied by an unparalleled mass migration and loss of life. Initially a Dominion of the British Commonwealth, Pakistan officially drafted its constitution in 1956, and emerged as a declared Islamic republic. In 1971, the exclave of East Pakistan seceded as the new country of Bangladesh after a nine-month-long civil war. In the following four decades, Pakistan has been ruled by governments whose descriptions, although complex, commonly alternated between civilian and military, democratic and authoritarian, relatively secular and Islamist. Pakistan elected a civilian government in 2008, and in 2010 adopted a parliamentary system with periodic elections.Pakistan is a regional and middle power nation, and has the world's sixth-largest standing armed forces. It is a declared nuclear-weapons state, and is ranked amongst the emerging and growth-leading economies, with a large and rapidly-growing middle class. Pakistan's political history since independence has been characterized by periods of significant economic and military growth as well as those of political and economic instability. It is an ethnically and linguistically diverse country, with similarly diverse geography and wildlife. However, the country continues to face challenges, including poverty, illiteracy, corruption and terrorism. Pakistan is a member of the United Nations, the Shanghai Cooperation Organisation, the Organisation of Islamic Cooperation, the Commonwealth of Nations, the South Asian Association for Regional Cooperation, and the Islamic Military Counter-Terrorism Coalition, and is designated as a major non-NATO ally by the United States.