UN Charter

Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

The 1945 founding treaty of the United Nations that establishes its organs, purposes, and the legal framework governing the use of force between states.
When did the UN Charter enter into force?
Can the UN Charter be amended?
What is the relationship between the Charter and other treaties?

Updated June 22, 2026

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Timeline

26 June 1945
The Charter of the United Nations was signed on in San Francisco by 50 states at the conclusion of the United Nations Conference on International Organizati…
24 October 1945
The Charter of the United Nations was signed on 26 June 1945 in San Francisco by 50 states at the conclusion of the United Nations Conference on Internationa…

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In 1990, the UN Security Council invoked Chapter VII of the UN Charter in Resolution 678 to authorize member states to use "all necessary means" to expel Iraqi forces from Kuwait.

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Timeline

26 June 1945

The Charter of the United Nations was signed on in San Francisco by 50 states at the conclusion of the United Nations Conference on International Organizati…

24 October 1945

The Charter of the United Nations was signed on 26 June 1945 in San Francisco by 50 states at the conclusion of the United Nations Conference on Internationa…

Research it like a delegate

The Charter of the United Nations was signed on 26 June 1945 in San Francisco by 50 states at the conclusion of the United Nations Conference on International Organization, and entered into force on 24 October 1945 after ratification by the five permanent Security Council members and a majority of other signatories. Poland signed later, bringing the original membership to 51. The Statute of the International Court of Justice is annexed to and forms an integral part of the Charter.

The Charter contains a Preamble and 111 articles organized into 19 chapters. Key provisions include:

Article 1 sets out the UN's purposes, chiefly maintaining international peace and security.
Article 2(4) prohibits the threat or use of force against the territorial integrity or political independence of any state.
Article 2(7) bars UN intervention in matters essentially within domestic jurisdiction, subject to Chapter VII enforcement.
Chapter VI governs pacific settlement of disputes; Chapter VII authorizes the Security Council to determine threats to the peace and impose sanctions or authorize force.
Article 51 preserves the inherent right of individual or collective self-defense.
Article 103 establishes that Charter obligations prevail over conflicting treaty obligations.
Article 27(3) gives the five permanent Security Council members (China, France, Russia, the UK, the US) the veto on non-procedural matters.

The Charter establishes six principal organs: the General Assembly, Security Council, Economic and Social Council, Trusteeship Council, International Court of Justice, and Secretariat. Amendments require a two-thirds vote of the General Assembly and ratification by two-thirds of members including all permanent Council members (Article 108). The Charter has been amended only a handful of times, most notably to expand Security Council membership from 11 to 15 in 1965.

It is widely regarded as the cornerstone of modern public international law and is binding on all 193 current member states.

Frequently asked questions

When did the UN Charter enter into force?

On 24 October 1945, after ratification by the five permanent Security Council members and a majority of other signatories. This date is commemorated annually as United Nations Day.

Can the UN Charter be amended?

Yes, under Article 108, amendments require approval by two-thirds of the General Assembly and ratification by two-thirds of UN members, including all five permanent members of the Security Council.

What is the relationship between the Charter and other treaties?

Article 103 provides that in the event of a conflict between obligations under the Charter and obligations under any other international agreement, Charter obligations prevail.