IU
- iu – (s) (s) Inuktitut language (ISO 639-1 code)
- IUCN – (i) International Union for the Conservation of Nature and Natural Resources (World Conservation Union)
- IUPAC – (a) International Union of Pure and Applied Chemistry (pronounced "eye-yoo-pac")
- IUSS – (i) Integrated Undersea Surveillance System – Integrated Unit Simulation System – International Union of Soil Sciences
Read more about this topic: List Of Acronyms And Initialisms: I