The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is the cornerstone of global efforts to prevent the spread of nuclear weapons, promote cooperation in the peaceful uses of nuclear energy, and further the goal of nuclear disarmament. Opened for signature on July 1, 1968, and entering into force on March 5, 1970, the treaty was extended indefinitely in 1995. With 191 States parties, the NPT is the most universally adhered-to multilateral agreement in the nuclear domain.

The issue of preventing nuclear proliferation was first formally raised at the 14th session of the UN General Assembly in 1959, within broader deliberations on disarmament. From 1959 to 1967, the General Assembly passed multiple resolutions urging the Conference of the Eighteen Nation Disarmament Committee (ENDC), established by the USSR and the USA, to prioritize the negotiation of a non-proliferation treaty.

non-proliferation treaty

The Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons opened this afternoon, 5 May, 1975 at the Palais des Nations in Geneva. UN Photo

Under the treaty, only nations that developed and tested nuclear weapons before January 1, 1967, are classified as nuclear-weapon states. These are the United States, the United Kingdom, France, China, and Russia. These countries have committed under the NPT to work toward eliminating their arsenals over time.

Cold War Origins

By the 1960s, the rapid dissemination of nuclear knowledge and the potential for further proliferation alarmed both nuclear and non-nuclear states. The Cold War rivalry and the doctrine of mutually assured destruction (MAD) heightened the urgency for a treaty to prevent the spread of nuclear weapons.

non-proliferation treaty

U.N. Secretary-General U Thant arrived here yesterday to attend the signing of the Nuclear Test-Ban Treaty by the representatives of the USSR, the United Kingdom and the United States. UN Photo

Following the Limited Test Ban Treaty (1963) and the Outer Space Treaty (1967), the NPT was the first major effort to curb nuclear arms expansion. Despite early reluctance, the U.S. and the USSR realized mutual strategic benefits in limiting proliferation, leading to the 1968 agreement.

non-proliferation treaty

A general view of the press conference held today in Geneva by Mian Arshad Husain (Pakistan), President of the UN Conference of Non-Nuclear-Weapon States, which opened in here on 29 August and will end tomorrow, 28 September 1968. UN Photo

At the 1995 NPT Review and Extension Conference, parties unanimously agreed to extend the treaty indefinitely. Since then, Review Conferences are held every five years to assess progress and compliance. These meetings function as periodic “health checks” for the global nuclear order.

However, challenges have arisen. In 2022, the Tenth NPT Review Conference failed to adopt a consensus outcome, with Russia opposing the final document. This marked a serious setback amid growing global tensions, including Russia’s war on Ukraine and instability in the Middle East.

Peaceful Use and Monitoring

non-proliferation treaty

Joint inspection teams of the International Atomic Energy Agency (IAEA) and the Special Commission have been charged with the task of investigating Iraq’s nuclear capacity. UN nuclear inspectors (in caps, at left) at the entrance to the Abu Gharaib Army barracks. UN Photo

The NPT has 11 articles which apply both to nuclear-weapon States (NWS) and non-nuclear-weapon States (NNWS). The treaty is built on three interconnected pillars:

  • Non-proliferation: Non-nuclear-weapon States parties commit not to manufacture or otherwise acquire nuclear weapons or explosive devices. Nuclear-weapon States parties (defined as those that detonated a nuclear device before 1 January 1967) commit not to assist any non-nuclear-weapon State in acquiring such weapons.
  • Disarmament: The treaty obliges all parties to pursue negotiations in good faith towards nuclear disarmament.
  • Peaceful Use of Nuclear Energy: The NPT promotes international cooperation in the peaceful uses of nuclear energy under appropriate safeguards to ensure non-diversion for weapons use. The treaty promotes cooperation and exchange of technology for peaceful nuclear applications, under strict international safeguards.

IAEA’s Verification Role

The treaty supports the right of all member states to access nuclear technology for peaceful purposes, such as energy production. However, it also includes safeguards to prevent that technology from being used to develop nuclear weapons. These safeguards are administered by the International Atomic Energy Agency (IAEA), which conducts inspections to verify compliance

non-proliferation treaty

An UNSCOM inspector checks an UNSCOM tag on a silkworm missile to ensure that it has not been tampered, either for cannibalization of vital parts or used for reverse engineering. [1995]. UN Photo/H. Arvidsson

Article III of the NPT requires all non-nuclear-weapon States to enter into Comprehensive Safeguards Agreements (CSAs) with the IAEA. These agreements enable the agency to verify the non-diversion of nuclear energy from peaceful purposes to nuclear weapons.

As of May 2023, 182 non-nuclear-weapon States parties have brought CSAs into force, with four yet to do so. The IAEA also plays a significant role under Article IV in facilitating peaceful nuclear applications that support the Sustainable Development Goals (SDGs)—in areas like energy, health, agriculture, and water management.

The 2017 Treaty on the Prohibition of Nuclear Weapons (TPNW)

non-proliferation treaty

The Treaty on the Prohibition of Nuclear Weapons, which was adopted on 7 July 2017 by 122 States, opened for signature on 20 September, on the sidelines of the annual general debate of the General Assembly. Secretary-General António Guterres speaks at the signing ceremony. UN Photo/Kim Haughton

In response to the limitations of the NPT, over 120 countries negotiated the Treaty on the Prohibition of Nuclear Weapons (TPNW), which entered into force in 2021. The TPNW:

  • Prohibits the development, testing, production, possession, and use of nuclear weapons.
  • Establishes a framework for the verifiable elimination of nuclear arsenals.
  • Mandates assistance to victims of nuclear testing and environmental remediation

Effectiveness and Criticism

The NPT enshrines an asymmetry: only five states (the US, UK, Russia, France, and China) are officially recognized as nuclear-weapon states. They retain their arsenals under the treaty, while other signatories are forbidden from developing them. In return, these five committed to eventual disarmament and assistance in peaceful nuclear energy.

non-proliferation treaty

Representatives the five Nuclear Non-Proliferation Treaty (NPT) nuclear-weapon states — China, France, Russia, the United Kingdom and the United States — also known as the “P5”, held a press conference on the outcome of the Fourth P5 Conference: On the Way to the 2015 NPT Review Conference, held on April 18-19, in Geneva. UN Photo/Jean Marc Ferré

Yet critics argue that NWS have failed to meet their disarmament obligations, continuing to modernize and expand their arsenals. The inequality has been a recurring point of contention, especially during NPT review conferences such as in 2005, where NNWS voiced dissatisfaction with the status quo.

non-proliferation treaty

At a joint declaration signing today, Mongolia reconfirmed its commitment to the Treaty on the Non-proliferation of Nuclear Weapons and the five permanent members of the UN Security Council (P5) affirmed their intent to respect Mongolia’s status and not to contribute to any act that would violate it. UN Photo/Eskinder Debebe

Despite its broad acceptance and successes in slowing proliferation, the NPT has faced persistent criticisms:

  • Unequal obligations: Non-nuclear states must permanently renounce nuclear weapons, while nuclear powers are not required to disarm immediately.
  • Slow progress on disarmament: Despite Article VI’s disarmament obligations, nuclear states continue to modernize arsenals.
  • Non-signatory nuclear states: India, Israel, and Pakistan never joined the treaty and developed nuclear weapons. North Korea withdrew in 2003 and later tested weapons.
  • Compliance issues: Concerns over programs in Iraq, Iran, and North Korea have challenged the NPT’s enforcement credibility.
non-proliferation treaty

Buddhist monks joining in a peace rally today in front of the United Nations Headquarters. The demonstrators were paying tribute to the UN before proceeding to a massive Peace Rally being held in Central Park to coincide with the UN General Assembly’s second Special Session on Disarmament. UN Photo/John Isaac

Iran and Current Tensions

Iran has been a signatory to the NPT since 1970 as a non-nuclear-weapon state. While it claims its nuclear program is for peaceful purposes, many Western nations and Israel suspect it has ambitions to develop nuclear weapons. These concerns intensified after the IAEA’s Board of Governors declared Tehran in breach of its NPT obligations in June 2025. The declaration followed findings that Iran had failed to explain uranium traces found at multiple undeclared sites.

non-proliferation treaty

This handout satellite image shows the Bushehr Reactor, Iran collected by Space Imaging’s IKONOS satellite 0n 01 March, 2001. The Iranian Nuclear facility located approximately 17 kilometers south of the city of Bushehr occupies a 2.5 Square Kilometer site area, which includes assembly halls, a concrete channel for cooling water that runs from the reactors to the Gulf, and a the harbor which supports loading and unloading of foreign materials needed for construction and reactor operation. Iran and Russia 27 February, 2005 signed a landmark nuclear fuel accord that paves the way for the firing up of the country’s first atomic power station, a project the United States alleges is part of a cover for weapons development. AFP PHOTO/SPACE IMAGING/HO

In response, Iranian officials have criticized the IAEA’s conclusions as politically motivated and emphasized their commitment to peaceful nuclear development. However, recent statements by Iranian authorities suggest that parliament is preparing a bill that could lead to Iran’s withdrawal from the treaty—an option allowed under the NPT if a country believes its national interests are under threat, provided it gives three months’ notice.

non-proliferation treaty

An anti-missile system operates as missiles are launched from Iran, as seen from Tel Aviv, Israel, June 18, 2025. REUTERS/Violeta Santos Moura

Looking Ahead: Road to 2026

The Eleventh NPT Review Conference, scheduled for 2026, presents a critical opportunity to restore momentum for disarmament and reinforce non-proliferation norms. The European Union, among others, has reaffirmed its commitment to universalizing the treaty and strengthening its implementation.

non-proliferation treaty

The Treaty on the Prohibition of Nuclear Weapons, which was adopted on 7 July 2017 by 122 States, opened for signature on 20 September, on the sidelines of the annual general debate of the General Assembly. The book of signatures at the signing ceremony. UN Photo/Kim Haughton