UO
UO is an abbreviation for:
- Hong Kong Express Airways, Chinese airline ( IATA code )
- Russian Federation in accordance with the ICAO code
- Ultima Online, an online role-playing game
- Reverse osmosis, a method for the extraction of ion -free water
- University of Oklahoma, the University of the State of Oklahoma
- University of Oregon, the University of the State of Oregon
- University of Ottawa, the University of the Canadian capital Ottawa
UO as distinguishing signs on license plate:
- Czech Republic: Okres Ústí nad Orlicí, German: Wild Sword ( discontinued)
- Disambiguation
- Abbreviation