| Acronym | Definition |
|---|
| USO | United Service Organizations (provides morale, welfare and recreation-type services to US uniformed military personnel) |
| USO | United States Oil Fund (stock symbol) |
| USO | Unión Sindical Obrera (Spanish: Workers Syndical Union; Spain) |
| USO | Universal Service Obligation |
| USO | University Symphony Orchestra (various universities) |
| USO | Utah Symphony Orchestra (est. 1940) |
| USO | Ultra Stable Oscillator |
| USO | United Solar Ovonic (various locations) |
| USO | United States Open |
| USO | Universal Service Order |
| USO | Unilateral Salpingo-Oophorectomy (surgical procedure) |
| USO | United Stars Organisation (science fiction) |
| USO | Universitair Symfonisch Orkest (University Symphony Orchestra; Leuven, Belgium) |
| USO | Unidentified Submarine Object |
| USO | Unit Security Officer |
| USO | Unidentified Submersible Object |
| USO | Unique Sink Orientation |
| USO | Unix Software Organization |
| USO | Union Sportive Oyonnax (French sports organization) |
| USO | Unidentified Superconducting Object |
| USO | Union Sportive Orléans (French sports organization) |
| USO | Utsjoen Sähköosuuskunta (electric supplier company of Utsjoki, Finland) |
| USO | Unidentified Sliding Object (vehicle) |
| USO | Under Secretary of the Navy's Office (US Navy) |
| USO | Undercover Special Operations |