International Union of Speleology
| Abbreviation | UIS |
|---|---|
| Formation | 1965 |
| Type | INGO |
| Headquarters | Titov trg 2, Postojna, Slovenia |
Region served | Worldwide |
| Membership | 58 countries |
Official language | English, French, German, Spanish, and Russian |
| Nadja Zupan-Hajna (Slovenia) | |
| Zdeněk Motyčka (Czech Republic), Nivaldo Colzato (Brazil) | |
| Johannes Mattes (Austria) | |
Parent organization | International Science Council (ISC) |
| Website | UIS Official website |
International Union of Speleology (French: Union Internationale de Spéléologie, UIS) is a scientific non-governmental organization dedicated to the international promotion and coordination of cave and karst research. Founded in 1965, UIS is a member of the International Science Council in Paris and cooperates with UNESCO. In 2021–2022, UIS organized the International Year of Caves and Karst.