​The TNP was signed on 1st July 1968 and came into force in 1970. It is the cornerstone of the fight against nuclear proliferation and is one of the foundations of the collective security system.

189 States are parties to the TNP. Among these States, the TNP makes a distinction between Nuclear Weapons States (NWS), defined as being those States which carried out a nuclear test before 1st January 1967, and the other States, called Non-Nuclear Weapons States (NNWS). There are 5 NWS: United States, Russia, United Kingdom, China and France. Three nuclear states are not parties to the TNP: India, Pakistan and Israel. North Korea officially withdrew from the TNP in 2003 (even if it intentionally maintains a degree of ambiguity with regard to its status in respect of the Treaty).

The TNP is based on three pillars, corresponding to the undertakings of the Parties:

• Disarmament (article VI):
  The NWS undertake to continue nuclear disarmament negotiations in good faith within the framework of general and complete disarmament. This is currently the only nuclear disarmament obligation on the NWS in a multilateral instrument.
• Nuclear non-proliferation:
  - Non-proliferation undertaking (articles I and II): The NWS undertake not to transfer nuclear weapons. The NNWS undertake not to attempt to acquire nuclear weapons.
  
  - Verification undertaking (article III): The NNWS undertake to conclude generalised safeguard agreements with the International Atomic Energy Agency to verify that nuclear materials and installations are not diverted for military purposes. The Parties must set up a system of controls on nuclear exports.
  

• Promotion of the peaceful uses of nuclear energy (article IV):
  the Parties undertake to facilitate exchanges of nuclear technologies for peaceful purposes and in particular to encourage cooperation with the developing countries.

The TNP was extended indefinitely in 1995 and provides for a Treaty review cycle every five years.