# List of treaties by number of parties

This article contains a list of treaties by number of parties to the treaty. A "party" to a treaty is a state or other entity that ratifies, accedes to, approves, or succeeds to the treaty.

## General principles of ratification

In general, multilateral treaties are open to ratification by any state. Some treaties may also be ratified by supranational bodies, such as the European Union, and by other international organizations.
In practice, the depositary of a treaty will usually only recognise ratifications of the treaty that are performed by a state that is recognised as a state at international law. A state can be formally recognised as such by becoming a member of the United Nations; there are currently 193 member states of the United Nations. The only non-UN states that undoubtedly meet the standard of statehood are the Cook Islands and Niue, who have had their "full treaty-making capacity" recognised by the United Nations Secretariat. The Holy See (Vatican City) is also widely recognised as being able to legitimately ratify treaties, and has been granted non-member observer state status by the UN General Assembly. Following the UNGA passing a resolution granting non-member observer state status to the State of Palestine, the UNSG has begun to recognize its right to ratify treaties. Ratifications performed by other states with more limited recognition—such as Abkhazia, the Republic of Artsakh (Nagorno-Karabakh), the Republic of China (Taiwan), Kosovo, Northern Cyprus, the Sahrawi Arab Democratic Republic (Western Sahara), Somaliland, South Ossetia, and Transnistria—have usually not been recognised by treaty depositaries as states that can ratify treaties, although there are some exceptions to this general rule.
If a state party to a treaty denounces the treaty, the state (often after a certain period before the denunciation takes effect) is no longer a party to the treaty, although in some cases certain parts of the treaty may continue to apply.

## Ratifications by defunct states

States change over time, and often a state that ratified a treaty will cease to exist. International law deals with this issue in two ways. First, it is possible for a state to be declared the successor state to the defunct state. In this situation, any ratifications performed by the defunct state are transferred to and attributed to the successor state. Examples of successor states are the Russian Federation (successor to the Soviet Union), People's Republic of China (successor to the mainland Republic of China), Serbia (successor to Serbia and Montenegro), Belarus (successor to the Byelorussian SSR), Ukraine (successor to the Ukrainian SSR), and Tanzania (successor to Tanganyika). It is possible for a single state to be the successor state of multiple states, as with Yemen being the successor state of both North Yemen and South Yemen.
Second, some states have no legal successor state but cease to exist; in such cases, the ratifications performed by the state are disregarded. In some cases, such states are subsumed into an existing state, as when East Germany merged into the Federal Republic of Germany, and when Zanzibar merged into Tanzania (at first United Republic of Tanganyika and Zanzibar). In other cases, the defunct state is divided into two or more states, with none of the states being designated as the formal successor state. Examples of the latter situation include SFR Yugoslavia (now six independent states) and Czechoslovakia (now two independent states). In this situation, the new states usually declare which treaties the defunct state ratified continue to have force for the new state. Such a declaration is regarded as a "ratification" by the new state.
For purposes of the numbers in this list, only ratifications, accessions, or successions of currently existing states are considered. No regard is given to ratifications by defunct states that have no current successor state.

## Maximum limits to ratification numbers

Due to these limitations, in 2021, the maximum number of state ratifications that a multilateral treaty can have is 198; this total consists of all 193 UN member states; both UN observer states, the Holy See (Vatican City) and the State of Palestine; as well as the Cook Islands, Niue, and Kosovo (member states of eight, five, and two UN specialized agencies respectively). If supranational or other international organizations ratify the treaty, the total number of ratifications may exceed 198.

## Legal effect of a high number of ratifications

When a treaty is ratified by nearly all recognized states in the world, the legal principles contained in the treaty may become customary international law. Customary international law applies to all states, whether or not the state has ratified a treaty that enshrines the principle. There is no set number of ratifications that are required to convert a treaty's principles into customary international law, and states and experts often disagree on what principles have and have not attained the status.

## List of treaties by number of parties

Below is the list of treaties by number of parties. Only treaties with a minimum of 170 parties are included.
| Treaty | Year concluded | Topic | UN | Non-UN | States | Other | Total | Non-parties |
| Vienna Convention for the Protection of the Ozone Layer | 1985 | Environment (ozone depletion) | 193 | 4 (COKVATNIUPSE) | 197 | 1 (EU) | 198 | — |
| Montreal Protocol | 1987 | Environment (ozone depletion) | 193 | 4 (COKVATNIUPSE) | 197 | 1 (EU) | 198 | — |
| UN Framework Convention on Climate Change | 1992 | Environment (climate change) | 193 | 4 (COKVATNIUPSE) | 197 | 1 (EU) | 198 | — |
| UN Convention to Combat Desertification | 1994 | Environment (desertification) | 193 | 3 (COKNIUPSE) | 196 | 1 (EU) | 197 | VAT |
| Geneva Conventions: First, Second, Third, Fourth | 1949 | International humanitarian law | 193 | 3 (COKVATPSE) | 196 | 0 | 196 | NIU |
| Convention on the Rights of the Child | 1989 | Human rights | 192 | 4 (COKVATNIUPSE) | 196 | 0 | 196 | USA |
| Convention concerning the Protection of the World Cultural and Natural Heritage | 1972 | Cultural and natural heritage | 192 | 4 (COKVATNIUPSE) | 196 | 0 | 196 | LIE |
| Convention on Biological Diversity | 1992 | Environment (species preservation; sustainable development) | 192 | 3 (COKNIUPSE) | 195 | 1 (EU) | 196 | VAT, USA |
| Constitution of the Food and Agriculture Organization | 1945 | Organizational (FAO); agriculture; food | 192 | 2 (COKNIU) | 194 | 1 (EU) | 195 | VAT, LIE, PSE |
| Paris Agreement | 2015 | Environment (climate change) | 190 | 4 (COKNIUPSEVAT) | 194 | 1 (EU) | 195 | IRN, LBY, YEM |
| Constitution and Convention of the International Telecommunication Union | 1865/1992 | Organizational (ITU); telecommunications | 193 | 1 (VAT) | 194 | 0 | 194 | COK, NIU, PSE |
| Constitution of the World Health Organization | 1946 | Organizational (WHO); health | 192 | 2 (COKNIU) | 194 | 0 | 194 | VAT, LIE, PSE |
| Constitution of the United Nations Educational, Scientific and Cultural Organisation | 1945 | Organizational (UNESCO); education; science; culture | 191 | 3 (COKNIUPSE) | 194 | 0 | 194 | VAT, ISR, LIE |
| United Nations Charter | 1945 | Organizational (UN); pacific settlement of disputes | 193 | 0 | 193 | 0 | 193 | COK, VAT, NIU, PSE |
| Chemical Weapons Convention | 1992 | Organizational (OPCW); international humanitarian law; arms control | 189 | 4 (COKVATNIUPSE) | 193 | 0 | 193 | EGY, ISR, PRK, SSD |
| Chicago Convention on International Civil Aviation | 1944 | Organizational (ICAO); air transport | 192 | 1 (COK) | 193 | 0 | 193 | VAT, LIE, NIU, PSE |
| Vienna Convention on Diplomatic Relations | 1961 | Privileges and immunities; diplomatic relations | 191 | 2 (VATPSE) | 193 | 0 | 193 | COK, NIU, PLW, SSD |
| WIPO Convention | 1967 | Organizational (WIPO); intellectual property | 190 | 3 (COKVATNIU) | 193 | 0 | 193 | FSM, PLW, PSE, SSD |
| Constitution of the International Criminal Police Organization | 1923/1956 | Organizational (Interpol); law enforcement cooperation | 191 | 2 (PSEVAT) | 193 | 0 | 193 | COK, NIU, PRK, TUV |
| Kyoto Protocol | 1997 | Environment (climate change) | 189 | 2 (COKNIU) | 191 | 1 (EU) | 192 | AND, CAN, VAT, PSE, SSD, USA |
| UN Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances | 1988 | Drug control | 187 | 4 (COKVATNIUPSE) | 191 | 1 (EU) | 192 | GNQ, KIR, PNG, SLB, SOM, TUV |
| United Nations Convention against Transnational Organized Crime | 2000 | Organized crime; international criminal law | 187 | 4 (COKVATNIUPSE) | 191 | 1 (EU) | 192 | COG, IRN, PNG, SLB, SOM, TUV |
| International Convention Against Doping in Sport | 2005 | Doping in sport | 190 | 2 (COKPSE) | 192 | 0 | 192 | AFG, GNB, LIE, NIU, VAT |
| Convention on the Rights of Persons with Disabilities | 2006 | Human rights | 189 | 2 (COKPSE) | 191 | 1 (EU) | 192 | VAT, LBN, NIU, TJK, TON, USA |
| Basel Convention | 1992 | Environmental (hazardous waste disposal) | 188 | 2 (COKPSE) | 190 | 1 (EU) | 191 | TLS, FJI, HTI, VAT, NIU, SSD, USA |
| United Nations Convention against Corruption | 2003 | International criminal law | 186 | 4 (COKVATNIUPSE) | 190 | 1 (EU) | 191 | AND, ERI, MCO, PRK, VCT, SMR, SYR |
| Articles of Agreement of the International Monetary Fund | 1944 | Organizational (IMF); international development | 190 | 1 (UNK) | 191 | 0 | 191 | COK, CUB, VAT, MCO, NIU, PRK, PSE |
| Treaty on the Non-Proliferation of Nuclear Weapons | 1968 | Arms control | 188 | 2 (VATPSE) | 190 | 0 | 190 | COK, IND, ISR, NIU, PRK, PAK, SSD |
| International Convention for the Suppression of the Financing of Terrorism | 1999 | Terrorism | 187 | 3 (COKVATNIU) | 190 | 0 | 190 | BDI, TCD, ERI, IRN, PSE, SOM, TUV |
| Convention on the Elimination of All Forms of Discrimination against Women | 1979 | Human rights | 187 | 2 (COKPSE) | 189 | 0 | 189 | VAT, IRN, PLW, NIU, SOM, SDN, TON, USA |
| Articles of Agreement of the International Bank for Reconstruction and Development | 1944 | Organizational (IBRD); international development | 188 | 1 (UNK) | 189 | 0 | 189 | AND, COK, CUB, VAT, LIE, MCO, NIU, PRK, PSE |
| Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation | 1971 | Aviation; terrorism | 186 | 2 (COKNIU) | 188 | 0 | 188 | TLS, ERI, VAT, KIR, PSE, SMR, SOM, SSD, TUV |
| Biological Weapons Convention | 1972 | International humanitarian law; arms control | 184 | 4 (COKVATNIUPSE) | 188 | 0 | 188 | TCD, DJI, ERI, EGY, HTI, ISR, KIR, SOM, SYR |
| Constitution of the Universal Postal Union | 1964 | Organizational (UPU); postal | 186 | 1 (VAT) | 187 | 0 | 187 | AND, DOM, HND, MHL, FSM, PLW, PSE, SDN |
| Constitution of the International Labour Organization | 1919/1945 | Organizational (ILO); labour | 186 | 1 (COK) | 187 | 0 | 187 | AND, BHU, VAT, LIE, FSM, MCO, NIU, PRK, NRU, PSE |
| Convention of the World Meteorological Organization | 1950 | Meteorology | 185 | 2 (COKNIU) | 187 | 0 | 187 | GNQ, GRD, LIE, MHL, PLW, KNA, VCN, SMR, PSE, VAT |
| Worst Forms of Child Labour Convention | 1999 | Human rights; labour | 186 | 1 (COK) | 187 | 0 | 187 | |
| Tokyo Convention | 1969 | Terrorism, air transport | 185 | 2 (COKNIU) | 187 | 0 | 187 | DMA, TLS, ERI, VAT, KIR, FSM, PSE, SOM, SSD, TUV |
| Single Convention on Narcotic Drugs | 1961 | Drug control | 184 | 2 (VATPSE) | 186 | 0 | 186 | TCD, COK, TLS, GNQ, KIR, NRU, WSM, SSD, TUV, VUT |
| Stockholm Convention on Persistent Organic Pollutants | 2001 | Environmental (persistent organic pollutants) | 182 | 3 (COKNIUPSE) | 185 | 1 (EU) | 186 | AND, BTN, BRN, TLS, HTI, VAT, ISR, MYS, SMR, SSD, TKM, USA |
| Articles of Agreement of the International Finance Corporation | 1955 | Organizational (IFC); international development | 185 | 1 (UNK) | 186 | 0 | 186 | AND, COK, CUB, VAT, LIE, MCO, NRU, NIU, PRK, PSE, SMR, VCT |
| Hague Hijacking Convention | 1970 | Terrorism, air transport | 183 | 2 (COKNIU) | 185 | 0 | 185 | BDI, TLS, ERI, VAT, KIR, FSM, PSE, SMR, SLB, SOM, SSD, TUV |
| International Plant Protection Convention | 1951 | Agricultural (pest protection) | 182 | 2 (COKNIU) | 184 | 1 (EU) | 185 | AND, AGO, BRN, KIR, LIE, MHL, MCO, NRU, PSE, SMR, TLS, TKM, VAT |
| Convention on Psychotropic Substances | 1971 | Drug control | 182 | 2 (VATPSE) | 184 | 0 | 184 | COK, TLS, GNQ, HTI, KIR, LBR, NRU, NIU, WSM, SLB, SSD, TUV, VUT |
| CITES | 1973 | Environmental (species preservation) | 183 | 0 | 183 | 1 (EU) | 184 | COK, HTI, KIR, MHL, FSM, NIU, NRU, PRK, PSE, SSD, TLS, TKM, TUV, VAT |
| WHO Framework Convention on Tobacco Control | 2003 | Health | 180 | 2 (COKNIU) | 182 | 1 (EU) | 183 | |
| Convention for the Safeguarding of the Intangible Cultural Heritage | 2003 | Cultural heritage | 181 | 2 (COKPSE) | 183 | 0 | 183 | |
| Vienna Convention on Consular Relations | 1963 | Privileges and immunities; diplomatic relations | 180 | 2 (VATPSE) | 182 | 0 | 182 | |
| International Convention on the Elimination of All Forms of Racial Discrimination | 1969 | Human rights | 180 | 2 (VATPSE) | 182 | 0 | 182 | |
| Convention establishing the Multilateral Investment Guarantee Agency | 1985 | Organizational (MIGA); international development | 181 | 1 (UNK) | 182 | 0 | 182 | |
| Protocol to Prevent, Suppress and Punish Trafficking in Persons, especially Women and Children | 2000 | Human rights; international criminal law (human trafficking) | 180 | 1 (PSE) | 181 | 1 (EU) | 182 | |
| Convention establishing a Customs Co-operation Council | 1950 | Organizational (WCO); customs | 180 | (UNK|PSE) | 182 | 0 | 182 | |
| Berne Convention for the Protection of Literary and Artistic Works | 1886 | Intellectual property (copyright) | 178 | 3 (COKVATNIU) | 181 | 0 | 181 | |
| Forced Labour Convention | 1930 | Human rights; labour | 180 | 1 (COK) | 181 | 0 | 181 | |
| Convention on the Prevention and Punishment of Crimes against Internationally Protected Persons, including Diplomatic Agents | 1973 | Anti-terrorism; privileges and immunities; diplomatic relations | 177 | 3 (VATNIUPSE) | 180 | 0 | 180 | |
| Paris Convention for the Protection of Industrial Property | 1883 | Intellectual property | 179 | 1 (VAT) | 180 | 0 | 180 | |
| Statute of the International Atomic Energy Agency | 1956 | Peaceful use of nuclear energy | 178 | 2 (COKVAT) | 180 | 0 | 180 | |
| Agreement establishing the International Fund for Agricultural Development | 1976 | Organizational (IFAD); development | 178 | 2 (COKNIU) | 180 | 0 | 180 | |
| Optional Protocol to the Convention on the Rights of the Child on the Sale of Children, Child Prostitution and Child Pornography | 2000 | Human rights | 176 | 2 (VATPSE) | 178 | 0 | 178 | |
| Comprehensive Nuclear-Test-Ban Treaty | 1996 (not in force) | Arms control | 175 | 3 (COKVATNIU) | 178 | 0 | 178 | |
| Abolition of Forced Labour Convention | 1957 | Human rights; labour | 175 | 1 (COK) | 176 | 0 | 176 | |
| International Convention against the Taking of Hostages | 1979 | Terrorism | 175 | 1 (NIU) | 176 | 0 | 176 | |
| Protocol for the Suppression of Unlawful Acts of Violence at Airports serving International Civil Aviation | 1988 | aviation; terrorism | 174 | 2 (COKNIU) | 176 | 0 | 176 | |
| Minimum Age Convention, 1973 | 1973 | Human rights; labour | 176 | 0 | 176 | 0 | 176 | |
| Convention on the International Maritime Organization | 1948 | Organizational (IMO); admiralty law; law of the sea | 175 | 1 (COK) | 176 | 0 | 176 | |
| Discrimination (Employment and Occupation) Convention | 1958 | Human rights; labour | 175 | 0 | 175 | 0 | 175 | |
| Constitution of the International Organization for Migration | 1953 | Migration | 173 | 2 (COKVAT) | 175 | 0 | 175 | |
| Articles of Agreement of the International Development Association | 1960 | Organizational (IDA); international development | 174 | 1 (UNK) | 175 | 0 | 175 | |
| Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment | 1984 | Human rights | 173 | 2 (VATPSE) | 175 | 0 | 175 | |
| Protocol I | 1977 | International humanitarian law | 171 | 3 (COKVATPSE) | 174 | 0 | 174 | |
| Equal Remuneration Convention | 1951 | Human rights; labour | 174 | 0 | 174 | 0 | 174 | |
| International Covenant on Civil and Political Rights | 1966 | Human rights | 173 | 1 (PSE) | 174 | 0 | 174 | |
| Cartagena Protocol on Biosafety | 2000 | Environment (species preservation; biological technology) | 170 | 2 (NIUPSE) | 172 | 1 (EU) | 173 | |
| Optional Protocol on the Involvement of Children in Armed Conflict | 2000 | Human rights | 171 | 2 (VATPSE) | 173 | 0 | 173 | |
| International Covenant on Economic, Social and Cultural Rights | 1976 | Human rights | 172 | 1 (PSE) | 173 | 0 | 173 | |
| Convention on Wetlands of International Importance especially as Waterfowl Habitat | 1971 | Environment (species preservation; waterfowl; wetlands) | 172 | 0 | 172 | 0 | 172 | |
| Convention on the Recognition and Enforcement of Foreign Arbitral Awards | 1958 | International arbitration | 169 | 3 (COKVATPSE) | 172 | 0 | 172 | |
| Constitution of the United Nations Industrial Development Organization | 1979 | Organizational (UNIDO); international development | 171 | 1 (PSE) | 172 | 0 | 172 | |
| International Convention for the Suppression of Terrorist Bombings | 1997 | Terrorism | 169 | 1 (NIU) | 170 | 0 | 170 | |
| United Nations Convention on the Law of the Sea | 1982 | law of the sea | 166 | 3 (COKNIUPSE) | 169 | 1 (EU) | 170 | |