thumb|250px|The [[United Nations Office at Geneva (Switzerland) is its second-biggest centre after the UN headquarters in New York City.]]

The Charter of the United Nations, also referred to as the UN Charter, is the foundational treaty of the United Nations. It establishes the purposes, governing structure, and overall framework of the United Nations System, including its principal organs: the Secretariat, the General Assembly, the Security Council, the Economic and Social Council, the International Court of Justice, and the Trusteeship Council. The UN Charter is an important part of public international law, and is the foundation for much of international law governing the use of force, pacific settlement of disputes, arms control, and other important functions of the maintenance of international peace and security.

According to its Charter, the purposes of the United Nations include reaffirming fundamental human rights; maintaining international peace and security; and promoting the economic and social advancement of all peoples. The UN Charter mandates the UN and its member states to maintain international peace and security, uphold international law, achieve "higher standards of living" for their citizens, address "economic, social, health, and related problems", and promote "universal respect for, and observance of, human rights and fundamental freedoms for all without distinction as to race, sex, language, or religion".<!-- History Channel is not a reliable source, see WP:RS/P --> As a charter and constituent treaty, its rules and obligations are binding on all members and supersede those of other treaties.

During the Second World War, the Allies (formally known as the United Nations) agreed to establish a new postwar international organization. it was signed in San Francisco, California, United States, by 50 of the 51 original member countries.

The Charter entered into force on 24 October 1945, following ratification by the five permanent members of the United Nations Security Council (United States, China, France, Soviet Union, and United Kingdom) and a majority of the other signatories; this is considered the official starting date of the United Nations, with the first session of the General Assembly, representing all 51 initial members, opening in London the following January. The General Assembly formally recognized 24 October as United Nations Day in 1947, and declared it an official international holiday in 1971. With 193 parties, most countries have now ratified the Charter.

Summary

thumb|Insignia appeared in the frontispiece of the charter, prototype of the current [[Flag of the United Nations|logo of the United Nations]]

The Charter consists of a preamble and 111 articles grouped into 19 chapters. The Declaration called for the "willing cooperation of free peoples" so that "all may enjoy economic and social security".

Roughly two months later, the United States and the United Kingdom issued a joint, eight-point statement elaborating such goals, known as the Atlantic Charter. It set out (1) that these countries do not seek aggrandizement, (2) that no territorial changes be made against the wishes of the people, (2) the right to self-determination for all peoples, (3) restoration of self-government to those deprived of it, (4) furtherance of access for all states to trade and raw materials "needed for their economic prosperity", (5) global cooperation to secure better economic and social conditions for the world, (6) the "destruction of the Nazi tyranny" and freedom from fear and want, (7) freedom of the seas, and (8) "abandonment of the use of force" by disarming nations of "aggression" and establishing a wider Anglo-American world "security system" under mutual disarmament after the war. Many of these principles would inspire or form part of the UN Charter.

The following year, on 1 January 1942, representatives of thirty nations formally at war with the Axis powers—led by the "Big Four" powers of China, the Soviet Union, the UK, and the U.S.—signed the Declaration by United Nations, which formalized the anti-Axis alliance and reaffirmed the purposes and principles of the Atlantic Charter. The following day, representatives of twenty-two other nations added their signatures. The term "United Nations" became synonymous with the Allies for the duration of the war, and was considered the formal name under which they were fighting. The Declaration by United Nations formed the basis of the United Nations Charter; virtually all nations that acceded to it would be invited to take part in the 1945 San Francisco Conference to discuss and prepare the Charter. This was the first formal announcement that a new international organization was being contemplated to replace the moribund League of Nations.

Pursuant to the Moscow Declarations, from 21 August 1944 to 7 October 1944, the U.S. hosted the Dumbarton Oaks Conference to develop a blueprint for what would become the United Nations. Many of the rules, principles, and provisions of the UN Charter were proposed during the conference, including the structure of the UN system; the creation of a "Security Council" to prevent future war and conflict; and the establishment of other "organs" of the organization, such as the General Assembly, International Court of Justice, and Secretariat. Conference delegates invited four more nations: the Belorussian Soviet Socialist Republic, the Ukrainian Soviet Socialist Republic, Argentina and recently liberated Denmark.

The conference was perhaps the largest international gathering up to that point, with 850 delegates, along with advisers and organizers, for a total of 3,500 participants.

thumb|right|World War II poster with the first line of the Preamble, "We the peoples of the United Nations"

Although the Preamble is an integral part of the Charter, it does not set out any of the rights or obligations of member states; its purpose is to serve as an interpretative guide for the provisions of the Charter through the highlighting of some of the core motives of the founders of the organization.

Chapter I: Purposes and Principles

Article 1

The Purposes of the United Nations are