Nuclear Non-Proliferation Treaty (NPT or NNPT) was signed on 1968 and came into force on 5 March 1970, to limit the spread or proliferation of nuclear weapons. Currently it has 189 member nations including five recognized nuclear nations - United States, Russia, China, France and United Kingdom. The four major non member nations are India, Pakistan, North Korea and Israel . The first 3 nations have openly tested nuclear weapons and declared that they possess nuclear weapons while Israel is yet to officially comment on their nuclear weapon program.

The NPT consists of a preamble and eleven articles and the treaty is interpreted as a three-pillar system
1. Non-proliferation - The five NWS (Nuclear weapon nations) agree not to transfer nuclear weapons or other nuclear explosive devices and  not in any way to assist, encourage, or induce a non-nuclear weapon state (NNWS) to acquire nuclear weapons.
2. Disarmament -  The treaty affirms the desire of its members to reduce the international tension prevailing due to nuclear weapons and to strengthen international trust so that a day will come for the halt to the production of nuclear weapons and finally dismantle them from the world.
3. The right to peacefully use nuclear technology. - It agrees upon the transfer of nuclear technology and materials to NPT signatory countries for the development of civilian nuclear energy programs in those countries, as long as they can demonstrate that their nuclear programs are not being used for the development of nuclear weapons.