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.
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.
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.
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.
Below is the list of treaties by number of parties. Only treaties with a minimum of 170 parties are included.
Treaty[3] | Year concluded | Topic | UN | Non-UN | States | Other | Total | Non-parties |
---|
Vienna Convention for the Protection of the Ozone Layer[4] | 1985 | Environment (ozone depletion) | 193 | 4 (COK VAT NIU PSE) | 197 | 1 (EU) | 198 | — |
Montreal Protocol[5] | 1987 | Environment (ozone depletion) | 193 | 4 (COK VAT NIU PSE) | 197 | 1 (EU) | 198 | — |
UN Framework Convention on Climate Change[6] | 1992 | Environment (climate change) | 193 | 4 (COK VAT NIU PSE) | 197 | 1 (EU) | 198 | — |
UN Convention to Combat Desertification[7] | 1994 | Environment (desertification) | 193 | 3 (COK NIU PSE) | 196 | 1 (EU) | 197 | VAT |
Geneva Conventions First,[8] Second,[9] Third,[10] Fourth[11]
| 1949 | International humanitarian law | 193 | 3 (COK VAT PSE) | 196 | 0 | 196 | NIU |
Convention on the Rights of the Child[12] | 1989 | Human rights | 192 | 4 (COK VAT NIU PSE) | 196 | 0 | 196 | USA |
Convention on Biological Diversity[13] | 1992 | Environment (species preservation; sustainable development) | 192 | 3 (COK NIU PSE) | 195 | 1 (EU) | 196 | VAT, USA |
Constitution of the United Nations Educational, Scientific and Cultural Organisation[14] | 1945 | Organizational (UNESCO); education; science; culture | 192 | 3 (COK NIU PSE) | 195 | 0 | 195 | VAT, LIE |
Constitution of the Food and Agriculture Organization[15] [16] | 1945 | Organizational (FAO); agriculture; food | 192 | 2 (COK NIU) | 194 | 1 (EU) | 195 | VAT, LIE, PSE |
Paris Agreement[17] | 2015 | Environment (climate change) | 190 | 4 (COK NIU PSE VAT) | 194 | 1 (EU) | 195 | IRN, LBY, YEM |
Convention concerning the Protection of the World Cultural and Natural Heritage[18] | 1972 | Cultural and natural heritage | 191 | 4 (COK VAT NIU PSE) | 195 | 0 | 195 | LIE, NRU |
Constitution of the World Health Organization[19] | 1946 | Organizational (WHO); health | 191 | 2 (COK NIU) | 193 | 0 | 193 | VAT, LIE, PSE |
United Nations Charter[20] | 1945 | Organizational (UN); pacific settlement of disputes | 193 | 0 | 193 | 0 | 193 | COK, VAT, NIU, PSE |
Constitution and Convention of the International Telecommunication Union[21] | 1865/1992[22] | Organizational (ITU); telecommunications | 192 | 1 (VAT) | 193 | 0 | 193 | COK, NIU, PLW, PSE |
Chemical Weapons Convention[23] | 1992 | Organizational (OPCW); international humanitarian law; arms control | 189 | 4 (COK VAT NIU PSE) | 193 | 0 | 193 | EGY, ISR, PRK, SSD |
Chicago Convention on International Civil Aviation[24] | 1944 | Organizational (ICAO); air transport | 192 | 1 (COK) | 193 | 0 | 193 | VAT, LIE, NIU, PSE |
Vienna Convention on Diplomatic Relations[25] | 1961 | Privileges and immunities; diplomatic relations | 191 | 2 (VAT PSE) | 193 | 0 | 193 | COK, NIU, PLW, SSD |
WIPO Convention[26] | 1967 | Organizational (WIPO); intellectual property | 190 | 3 (COK, VAT, NIU) | 193 | 0 | 193 | FSM, PLW, PSE, SSD |
Constitution of the International Criminal Police Organization[27] | 1923/1956 | Organizational (Interpol); law enforcement cooperation | 191 | 2 (PSE VAT) | 193 | 0 | 193 | COK, NIU, PRK, TUV |
Kyoto Protocol[28] | 1997 | Environment (climate change) | 189 | 2 (COK NIU) | 191 | 1 (EU) | 192 | AND, CAN, VAT, PSE, SSD, USA |
UN Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances[29] | 1988 | Drug control | 187 | 4 (COK VAT NIU PSE) | 191 | 1 (EU) | 192 | GNQ, KIR, PNG, SLB, SOM, TUV |
United Nations Convention against Transnational Organized Crime[30] | 2000 | Organized crime; international criminal law | 187 | 4 (COK VAT NIU PSE) | 191 | 1 (EU) | 192 | COG, IRN, PNG, SLB, SOM, TUV |
International Convention Against Doping in Sport[31] | 2005 | Doping in sport | 189 | 2 (COK PSE) | 191 | 0 | 191 | AFG, GNB, LIE, NIU, SSD, VAT |
Basel Convention[32] | 1992 | Environmental (hazardous waste disposal) | 188 | 2 (COK PSE) | 190 | 1 (EU) | 191 | TLS, FJI, HTI, VAT, NIU, SSD, USA |
United Nations Convention against Corruption[33] | 2003 | International criminal law | 186 | 4 (COK VAT NIU PSE) | 190 | 1 (EU) | 191 | AND, ERI, MCO, PRK, VCT, SMR, SYR |
Convention on the Rights of Persons with Disabilities[34] | 2006 | Human rights | 188 | 2 (COK PSE) | 190 | 1 (EU) | 191 | ERI, VAT, LBN, NIU, TJK, TON, USA |
Treaty on the Non-Proliferation of Nuclear Weapons[35] | 1968 | Arms control | 188 | 2 (VAT, PSE) | 190 | 0 | 190 | COK, IND, ISR, NIU, PRK, PAK, SSD |
Articles of Agreement of the International Monetary Fund[36] | 1944 | Organizational (IMF); international development | 189 | 1 (UNK) | 190 | 0 | 190 | COK, CUB, VAT, LIE, MCO, NIU, PRK, PSE |
International Convention for the Suppression of the Financing of Terrorism[37] | 1999 | Terrorism | 187 | 3 (COK VAT NIU) | 190 | 0 | 190 | BDI, TCD, ERI, IRN, PSE, SOM, TUV |
Convention on the Elimination of All Forms of Discrimination against Women[38] | 1979 | Human rights | 187 | 2 (COK PSE) | 189 | 0 | 189 | VAT, IRN, PLW, NIU, SOM, SDN, TON, USA |
Articles of Agreement of the International Bank for Reconstruction and Development[39] | 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[40] | 1971 | Aviation; terrorism | 186 | 2 (COK NIU) | 188 | 0 | 188 | TLS, ERI, VAT, KIR, PSE, SMR, SOM, SSD, TUV |
Constitution of the Universal Postal Union[41] | 1964 | Organizational (UPU); postal | 186 | 1 (VAT) | 187 | 0 | 187 | AND, DOM, HND, MHL, FSM, PLW, PSE, SDN |
Constitution of the International Labour Organization[42] | 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[43] | 1950 | Meteorology | 185 | 2 (COK NIU) | 187 | 0 | 187 | GNQ, GRD, LIE, MHL, PLW, KNA, VCN, SMR, PSE, VAT |
Worst Forms of Child Labour Convention[44] | 1999 | Human rights; labour | 186 | 1 (COK) | 187 | 0 | 187 | |
Tokyo Convention[45] | 1969 | Terrorism, air transport | 185 | 2 (COK NIU) | 187 | 0 | 187 | DMA, TLS, ERI, VAT, KIR, FSM, PSE, SOM, SSD, TUV |
Biological Weapons Convention[46] | 1972 | International humanitarian law; arms control | 183 | 4 (COK VAT NIU PSE) | 187 | 0 | 187 | TCD, COM, DJI, ERI, EGY, HTI, ISR, KIR, SOM, SYR |
Single Convention on Narcotic Drugs[47] | 1961 | Drug control | 184 | 2 (VAT PSE) | 186 | 0 | 186 | TCD, COK, TLS, GNQ, KIR, NRU, WSM, SSD, TUV, VUT |
Stockholm Convention on Persistent Organic Pollutants[48] | 2001 | Environmental (persistent organic pollutants) | 182 | 3 (COK NIU PSE) | 185 | 1 (EU) | 186 | AND, BTN, BRN, TLS, HTI, VAT, ISR, MYS, SMR, SSD, TKM, USA |
Articles of Agreement of the International Finance Corporation[49] | 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[50] | 1970 | Terrorism, air transport | 183 | 2 (COK NIU) | 185 | 0 | 185 | BDI, TLS, ERI, VAT, KIR, FSM, PSE, SMR, SLB, SOM, SSD, TUV |
International Plant Protection Convention[51] | 1951 | Agricultural (pest protection) | 182 | 2 (COK NIU) | 184 | 1 (EU) | 185 | |
Convention on Psychotropic Substances[52] | 1971 | Drug control | 182 | 2 (VAT PSE) | 184 | 0 | 184 | COK, TLS, GNQ, HTI, KIR, LBR, NRU, WSM, SLB, SSD, TUV, VUT |
CITES[53] | 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[54] | 2003 | Health | 180 | 2 (COK NIU) | 182 | 1 (EU) | 183 | |
Vienna Convention on Consular Relations[55] | 1963 | Privileges and immunities; diplomatic relations | 180 | 2 (VAT PSE) | 182 | 0 | 182 | |
International Convention on the Elimination of All Forms of Racial Discrimination[56] | 1969 | Human rights | 180 | 2 (VAT PSE) | 182 | 0 | 182 | |
Convention establishing the Multilateral Investment Guarantee Agency[57] | 1985 | Organizational (MIGA); international development | 181 | 1 (UNK) | 182 | 0 | 182 | |
Convention for the Safeguarding of the Intangible Cultural Heritage[58] | 2003 | Cultural heritage | 180 | 2 COK PSE) | 182 | 0 | 182 | |
Protocol to Prevent, Suppress and Punish Trafficking in Persons, especially Women and Children[59] | 2000 | Human rights; international criminal law (human trafficking) | 180 | 1 (PSE) | 181 | 1 (EU) | 182 | |
Berne Convention for the Protection of Literary and Artistic Works[60] | 1886 | Intellectual property (copyright) | 178 | 3 (COK VAT NIU) | 181 | 0 | 181 | |
Forced Labour Convention[61] | 1930 | Human rights; labour | 180 | 1 (COK) | 181 | 0 | 181 | |
Convention establishing a Customs Co-operation Council[62] | 1950 | Organizational (WCO); customs | 179 | 1 (UNK PSE) | 181 | 0 | 181 | |
Convention on the Prevention and Punishment of Crimes against Internationally Protected Persons, including Diplomatic Agents[63] | 1973 | Anti-terrorism; privileges and immunities; diplomatic relations | 177 | 3 (VAT NIU PSE) | 180 | 0 | 180 | |
Paris Convention for the Protection of Industrial Property[64] | 1883 | Intellectual property | 178 | 1 (VAT) | 179 | 0 | 179 | |
Statute of the International Atomic Energy Agency[65] | 1956 | Peaceful use of nuclear energy | 177 | 1 (VAT) | 178 | 0 | 178 | |
Optional Protocol to the Convention on the Rights of the Child on the Sale of Children, Child Prostitution and Child Pornography[66] | 2000 | Human rights | 176 | 2 (VAT PSE) | 178 | 0 | 178 | |
Agreement establishing the International Fund for Agricultural Development[67] | 1976 | Organizational (IFAD); development | 176 | 2 (COK NIU) | 178 | 0 | 178 | |
Comprehensive Nuclear-Test-Ban Treaty[68] (not in force) | 1996 | Arms control | 175 | 3 (COK VAT NIU) | 178 | 0 | 178 | |
Abolition of Forced Labour Convention[69] | 1957 | Human rights; labour | 175 | 1 (COK) | 176 | 0 | 176 | |
International Convention against the Taking of Hostages[70] | 1979 | Terrorism | 175 | 1 (NIU) | 176 | 0 | 176 | |
Protocol for the Suppression of Unlawful Acts of Violence at Airports serving International Civil Aviation[71] | 1988 | aviation; terrorism | 174 | 2 (COK NIU) | 176 | 0 | 176 | |
Minimum Age Convention, 1973[72] | 1973 | Human rights; labour | 176 | 0 | 176 | 0 | 176 | |
Discrimination (Employment and Occupation) Convention[73] | 1958 | Human rights; labour | 175 | 0 | 175 | 0 | 175 | |
Convention on the International Maritime Organization[74] [75] | 1948 | Organizational (IMO); admiralty law; law of the sea | 174 | 1 (COK) | 175 | 0 | 175 | |
Constitution of the International Organization for Migration[76] | 1953 | Migration | 173 | 2 (COK VAT) | 175 | 0 | 175 | |
Protocol I[77] | 1977 | International humanitarian law | 171 | 3 (COK VAT PSE) | 174 | 0 | 174 | |
Articles of Agreement of the International Development Association[78] | 1960 | Organizational (IDA); international development | 173 | 1 (UNK) | 174 | 0 | 174 | |
Equal Remuneration Convention[79] | 1951 | Human rights; labour | 174 | 0 | 174 | 0 | 174 | |
International Covenant on Civil and Political Rights[80] | 1966 | Human rights | 173 | 1 (PSE) | 174 | 0 | 174 | |
Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment[81] | 1984 | Human rights | 172 | 2 (VAT PSE) | 174 | 0 | 174 | |
Cartagena Protocol on Biosafety[82] | 2000 | Environment (species preservation; biological technology) | 170 | 2 (NIU PSE) | 172 | 1 (EU) | 173 | |
Optional Protocol on the Involvement of Children in Armed Conflict[83] | 2000 | Human rights | 171 | 2 (VAT PSE) | 173 | 0 | 173 | |
Convention on Wetlands of International Importance especially as Waterfowl Habitat[84] | 1971 | Environment (species preservation; waterfowl; wetlands) | 172 | 0 | 172 | 0 | 172 | |
Convention on the Recognition and Enforcement of Foreign Arbitral Awards[85] | 1958 | International arbitration | 169 | 3 (COK VAT PSE) | 172 | 0 | 172 | |
Constitution of the United Nations Industrial Development Organization[86] | 1979 | Organizational (UNIDO); international development | 171 | 1 (PSE) | 172 | 0 | 172 | |
International Covenant on Economic, Social and Cultural Rights[87] | 1976 | Human rights | 171 | 1 (PSE) | 172 | 0 | 172 | |
International Convention for the Suppression of Terrorist Bombings[88] | 1997 | Terrorism | 169 | 1 (NIU) | 170 | 0 | 170 | |
United Nations Convention on the Law of the Sea[89] | 1982 | law of the sea | 166 | 3 (COK NIU PSE) | 169 | 1 (EU) | 170 | | |