List of parties to the Treaty on the Non-Proliferation of Nuclear Weapons

[[Image:NPT Participation.svg|right|400px|thumb|Participation in the Nuclear Non-Proliferation Treaty

{{legend|#00aa00|Signed and ratified}} {{legend|#008000|Acceded or succeeded}} {{legend|#eeee00|Unrecognized state, abiding by treaty}}

{{legend|orange|Withdrawn}} {{legend|#ff1111|Non-signatory}} ]]

The list of parties to the Nuclear Non-Proliferation Treaty encompasses the states which have signed and ratified or acceded to the international agreement limiting the spread of nuclear weapons.

On 1 July 1968, the Nuclear Non-Proliferation Treaty (NPT) was opened for signature. Russia (a successor of the Soviet Union), the United Kingdom, and the United States are the three depositary states; states wishing to become a party to the NPT must deposit their instruments of ratification, accession or succession at the respective capitals of the depositary states: London, Moscow, and Washington, D.C.. The treaty came into force and closed for signature on 5 March 1970 with the deposit of ratification of the three depositary states and 40 others. Since then, states that did not sign the treaty may only accede to it, which China and France did in 1992. As of July 2011, 189 states are recognized as parties to the treaty. Montenegro is the most recent state to have joined, having submitted its instrument of succession on 3 June 2006. In addition, the Republic of China (Taiwan), which is currently only recognized by, ratified the treaty prior to the United Nations General Assembly's vote to transfer China's seat to the People's Republic of China (PRC) in 1971; Taiwan has accepted comprehensive IAEA safeguards and the measures of the Additional Protocol to verify that its nuclear program is entirely peaceful. North Korea was a party to the treaty but announced its withdrawal on 10 January 2003; its withdrawal became effective ninety days later. However, there is disagreement among the parties to the treaty whether North Korea's withdrawal was in conformity with the terms of the treaty. Four UN member states have never signed the treaty: India, Israel, Pakistan and South Sudan. The Cook Islands and Niue, two associated states of New Zealand which have had their "full treaty-making capacity" recognised by United Nations Secretariat, are not parties to the treaty but consider themselves bound by its provisions by virtue of their administration by New Zealand when the latter ratified the NPT.

The NPT remains the most widely subscribed to arms control treaty in history.

Ratified or acceded states
188 UN member states and observer Holy See are parties to the NPT.

Multiple dates indicate the different days in which states submitted their signature or deposition, varied by location. This location is noted by: (L) for London, (M) for Moscow, and (W) for Washington D.C.

Unrecognized state, abiding by treaty
The Republic of China (Taiwan), which is currently only recognized by, ratified the treaty prior to the United Nations General Assembly's vote to transfer China's seat to the People's Republic of China (PRC) in 1971. When the PRC subsequently ratified the treaty, they described the Republic of China's (ROC) ratification as "illegal". The ROC has committed itself to continue to adhere to the requirements of the treaty, and the United States has declared that they still consider them to be "bound by its obligations".

Withdrawn state
North Korea was a party to the treaty but announced its withdrawal on 10 January 2003; its withdrawal became effective ninety days later. However, there is disagreement among the parties to the treaty whether North Korea's withdrawal was in conformity with the terms of the treaty.

Non-signatory states
Four UN member states have never signed the treaty. The Cook Islands and Niue, two associated states of New Zealand which have had their "full treaty-making capacity" recognised by United Nations Secretariat, are not parties to the treaty but consider themselves bound by its provisions by virtue of their administration by New Zealand when the latter ratified the NPT.