UO

UO may stand for:
*UO, Hong Kong Express, airline IATA code
*UO, Ultima Online, a multiplayer online role-playing game
*UO, Unexploded ordnance, explosive weapons that did not explode when employed and pose a current risk
*Union Railroad (Oregon) or UO,
*UO, Underoath, an American metalcore/screamo band

In universities:
*UO, University of Oklahoma, USA
*UO, University of Oregon, USA

ee also

*U of O (disambiguation)