As of October 2013, 189 recognized states are party to the Nuclear Non-Proliferation Treaty (NPT). Montenegro was the most recent signatory from June 2006. North Korea withdrew its signature in January 2003. Three countries - India, Israel, & Pakistan - have never signed.
| Country | Date of Signature | Date of Ratification | Method |
|
| |||
| Afghanistan | July 1, 1968 | February 4, 1970 | Ratification |
| Albania | | September 12, 1990 | Accession |
| Algeria | | January 12, 1995 | Accession |
| Andorra | | June 7, 1996 | Accession |
| Antigua and Barbuda | | June 17, 1985 | Succession (from UK) |
| Angola | | October 15, 1996 | Accession |
| Argentina | | February 10, 1995 | Accession |
| Armenia | | June 21, 1993 | Accession |
| Australia | February 27, 1970 | January 23, 1973 | Ratification |
| Austria | July 1, 1968 | June 27, 1969 | Ratification |
| Azerbaijan | | September 22, 1992 | Accession |
| Bahamas | | August 11, 1976 | Succession (from UK) |
| Bahrain | | November 3, 1988 | Accession |
| Bangladesh | | August 31, 1979 | Accession |
| Barbados | July 1, 1968 | February 21, 1980 | Ratification |
| Belarus | | February 9, 1993 | Accession |
| Belgium | August 20, 1968 | May 2, 1975 | Ratification |
| Belize | | August 9, 1985 | Succession (from UK) |
| Benin | July 1, 1968 | October 31, 1972 | Ratification |
| Bhutan | | May 23, 1985 | Accession |
| Bolivia | July 1, 1968 | May 26, 1970 | Ratification |
| Bosnia & Herzegovina | | August 15, 1994 | Succession (from Yugoslavia) |
| Botswana | July 1, 1968 | April 28, 1969 | Ratification |
| Brazil | | September 18, 1998 | Accession |
| Brunei | | March 26, 1985 | Accession |
| Bulgaria | July 1, 1968 | September 5, 1969 | Ratification |
| Burkina Faso | November 25, 1968 | March 3, 1970 | Ratification |
| Burundi | | March 19, 1971 | Accession |
| Cambodia | | June 2, 1972 | Accession |
| Cameroon | July 17, 1968 | January 8, 1969 | Ratification |
| Canada | July 23, 1968 | January 8, 1969 | Ratification |
| Cape Verde | | October 24, 1979 | Accession |
| Central African Republic | | October 25, 1970 | Accession |
| Chad | July 1, 1968 | March 10, 1971 | Ratification |
| Chile | | May 25, 1995 | Accession |
| China | | March 9, 1992 | Accession |
| Colombia | July 1, 1968 | April 8, 1986 | Ratification |
| Comoros | | October 4, 1995 | Accession |
| Congo | | October 23, 1978 | Accession |
| Costa Rica | July 1, 1968 | March 3, 1970 | Ratification |
| Cote d'Ivoire | July 1, 1968 | March 6, 1973 | Ratification |
| Croatia | | June 29, 1992 | Succession (from Yugoslavia) |
| Cyprus | July 1, 1968 | February 10, 1970 | Ratification |
| Czech Republic | | January 1, 1993 | Succession (from Czechoslovakia) |
| Democratic Republic of Congo | July 22, 1968 | August 4, 1970 | Ratification (as Zaire) |
| Denmark | July 1, 1968 | January 3, 1969 | Ratification |
| Djibouti | | October 16, 1996 | Accession |
| Dominica | | August 10, 1984 | Succession (from UK) |
| Dominican Republic | July 1, 1968 | July 24, 1971 | Ratification |
| Ecuador | July 9, 1968 | March 7, 1969 | Ratification |
| Egypt | July 1, 1968 | February 26, 1981 | Ratification |
| El Salvador | July 1, 1968 | July 11, 1972 | Ratification |
| Equatorial Guinea | | November 1, 1984 | Accession |
| Eritrea | | March 16, 1995 | Accession |
| Estonia | | January 7, 1992 | Accession |
| Ethiopia | September 5, 1968 | February 5, 1970 | Ratification |
| Fiji | | July 21, 1972 | Succession (from UK) |
| Finland | July 1, 1968 | February 5, 1969 | Ratification |
| France | | August 2, 1992 | Accession |
| Gabon | | February 19, 1974 | Accession |
| The Gambia | September 4, 1968 | May 12, 1975 | Ratification |
| Georgia | | March 7, 1994 | Accession |
| Germany | November 28, 1969 | May 2, 1975 | Ratification (as West Germany) |
| Ghana | July 1, 1968 | May 4, 1970 | Ratification |
| Greece | July 1, 1968 | March 11, 1970 | Ratification |
| Grenada | | September 2, 1975 | Succession (from UK) |
| Guatemala | July 26, 1968 | September 22, 1970 | Ratification |
| Guinea | | April 29, 1985 | Accession |
| Guinea-Bissau | | August 20, 1976 | Accension |
| Guyana | | October 19, 1993 | Accession |
| Haiti | July 1, 1968 | June 2, 1970 | Ratification |
| Holy See | | February 25, 1971 | Accession |
| Honduras | July 1, 1968 | May 16, 1973 | Ratification |
| Hungary | July 1, 1968 | May 27, 1969 | Ratification |
| Iceland | July 1, 1968 | May 18, 1969 | Ratification |
| Indonesia | March 2, 1970 | July 12, 1979 | Ratification |
| Iran | July 1, 1968 | February 2, 1970 | Ratification |
| Iraq | July 1, 1968 | October 29, 1969 | Ratification |
| Ireland | July 1, 1968 | July 1, 1968 | Ratification |
| Italy | January 28, 1969 | May 2, 1975 | Ratification |
| Jamaica | April 14, 1969 | March 5, 1970 | Ratification |
| Japan | February 3, 1970 | June 8, 1976 | Ratification |
| Jordan | July 10, 1968 | February 11, 1970 | Ratification |
| Kazakhstan | | February 14, 1994 | Accession |
| Kenya | July 1, 1968 | June 11, 1970 | Ratification |
| Kiribati | | April 18, 1985 | Succession (from UK) |
| Korea, South | July 1, 1968 | April 23, 1975 | Ratification |
| Kuwait | August 15, 1968 | November 17, 1989 | Ratification |
| Kyrgyzstan | | July 5, 1994 | Accession |
| Laos | July 1, 1968 | February 20, 1970 | Ratification |
| Latvia | | January 31, 1992 | Accession |
| Lebanon | July 1, 1968 | July 15, 1970 | Ratification |
| Lesotho | July 1, 1968 | May 20, 1970 | Ratification |
| Liberia | July 1, 1968 | March 5, 1970 | Ratification |
| Libya | July 18, 1968 | May 26, 1975 | Ratification |
| Liechtenstein | | April 20, 1978 | Accession |
| Lithuania | | September 23, 1991 | Accession |
| Luxembourg | August 14, 1968 | May 2, 1975 | Ratification |
| Macedonia | | March 30, 1995 | Succession (from Yugoslavia) |
| Madagascar | August 22, 1968 | October 8, 1970 | Ratification |
| Malawi | | February 18, 1986 | Accession |
| Malaysia | July 1, 1968 | March 5, 1970 | Ratification |
| Maldive Islands | September 11, 1968 | April 7, 1970 | Ratification |
| Mali | July 14, 1969 | February 10, 1970 | Ratification |
| Malta | April 17, 1969 | February 6, 1970 | Ratification |
| Marshall Islands | | January 30, 1995 | Accession |
| Mauritania | | October 26, 1993 | Accession |
| Mauritius | July 1, 1968 | April 8, 1969 | Ratification |
| Mexico | July 26, 1968 | January 21, 1969 | Ratification |
| Micronesia | | April 14, 1995 | Accession |
| Moldova | | October 11, 1994 | Accession |
| Monaco | | March 13, 1995 | Accession |
| Mongolia | July 1, 1968 | May 15, 1969 | Ratification |
| Montenegro | June 3, 2006 | Accension | |
| Morocco | July 1, 1968 | November 27, 1970 | Ratification |
| Mozambique | | September 4, 1990 | Accession |
| Myanmar | | December 2, 1992 | Accession |
| Namibia | | October 2, 1992 | Accession |
| Nauru | | June 7, 1982 | Accession |
| Nepal | July 1, 1968 | January 5, 1970 | Ratification |
| Netherlands | August 20, 1968 | May 2, 1975 | Ratification |
| New Zealand | July 1, 1968 | September 10, 1969 | Ratification |
| Nicaragua | July 1, 1968 | March 6, 1973 | Ratification |
| Niger | | October 9, 1992 | Accession |
| Nigeria | July 1, 1968 | September 27, 1968 | Ratification |
| Norway | July 1, 1968 | February 5, 1969 | Ratification |
| Oman | | January 23, 1997 | Accession |
| Palau | | April 14, 1995 | Accession |
| Panama | July 1, 1968 | January 13, 1977 | Ratification |
| Papua New Guinea | | January 13, 1982 | Accession |
| Paraguay | July 1, 1968 | February 4, 1970 | Ratification |
| Peru | July 1, 1968 | March 3, 1970 | Ratification |
| Philippines | July 1, 1968 | October 5, 1972 | Ratification |
| Poland | July 1, 1968 | June 12, 1969 | Ratification |
| Portugal | | December 15, 1977 | Accession |
| Qatar | | April 3, 1989 | Accession |
| Romania | July 1, 1968 | February 4, 1970 | Ratification |
| Russia | July 1, 1968 | March 5, 1970 | Ratification (as USSR) |
| Rwanda | | May 20, 1975 | Accession |
| St. Kitts and Nevis | | November 6, 1984 | Succession (from UK) |
| St. Lucia | | December 28, 1979 | Succession (from UK) |
| St. Vincent & Grenadines | | November 6, 1984 | Succession (from UK) |
| San Marino | July 1, 1968 | August 10, 1970 | Ratification |
| Sao Tome & Principe | | July 20, 1983 | Accession |
| Saudi Arabia | | October 3, 1988 | Accession |
| Senegal | July 1, 1968 | December 17, 1970 | Ratification |
| Serbia | January 1, 1993 | Succession (from Yugoslavia) | |
| Seychelles | | March 12, 1985 | Accession |
| Sierra Leone | | February 26, 1975 | Accession |
| Singapore | February 5, 1970 | March 10, 1976 | Ratification |
| Slovakia | | January 1, 1993 | Succession (from Czechoslovakia) |
| Slovenia | | April 7, 1992 | Succession (from Yugoslavia) |
| Solomon Islands | | June 17, 1981 | Succession (from UK) |
| Somalia | July 1, 1968 | March 5, 1970 | Ratification |
| South Africa | | July 10, 1991 | Accession |
| Spain | | November 5, 1987 | Accession |
| Sri Lanka | July 1, 1968 | March 5, 1979 | Ratification |
| Sudan | December 24, 1968 | October 31, 1973 | Ratification |
| Suriname | | June 30, 1976 | Succession (from Netherlands) |
| Swaziland | June 24, 1969 | December 11, 1969 | Ratification |
| Sweden | August 19, 1968 | January 9, 1970 | Ratification |
| Switzerland | November 27, 1969 | March 9, 1977 | Ratification |
| Syrian Arab Republic | July 1, 1968 | September 24, 1969 | Ratification |
| Taiwan | July 1, 1968 | January 27, 1970 | Ratification |
| Tajikistan | | January 17, 1994 | Accession |
| Tanzania | | May 31, 1991 | Accession |
| Thailand | | December 7, 1972 | Accession |
| Togo | July 1, 1968 | February 26, 1970 | Ratification |
| Tonga | | July 7, 1971 | Succession (from UK) |
| Trinidad & Tobago | August 20, 1968 | October 30, 1968 | Ratification |
| Tunisia | July 1, 1968 | February 26, 1970 | Ratification |
| Turkey | January 28, 1969 | April 17, 1980 | Ratification |
| Tuvalu | | January 19, 1979 | Succession (from UK) |
| Turkmenistan | | September 29, 1994 | Accession |
| Uganda | | October 20, 1982 | Accession |
| Ukraine | | December 5, 1994 | Accession |
| United Arab Emirates | | September 26, 1995 | Accession |
| United Kingdom | July 1, 1968 | November 27, 1968 | Ratification |
| United States | July 1, 1968 | March 5, 1970 | Ratification |
| Uruguay | July 1, 1968 | August 31, 1970 | Ratification |
| Uzbekistan | | May 7, 1992 | Accession |
| Vanuatu | | August 24, 1995 | Accession |
| Venezuela | July 1, 1968 | September 25, 1975 | Ratification |
| Vietnam | | June 14, 1982 | Accession |
| Yemen | November 14, 1968 | June 1, 1979 | Ratification (as North Yemen) |
| Zambia | | May 15, 1991 | Accession |
| Zimbabwe | | September 26, 1991 | Accession |
Sources: Federation of American Scientists