HOO
| Acronym | Definition |
|---|---|
| HOO | Heroes of Olympus |
| HOO | Hours of Operation (various organizations) |
| HOO | Head of Operations |
| HOO | Hood River, Oregon (Amtrak station code) |
| HOO | Hrvatski Olimpijski Odbor (Croatian Olympic Committee) |
| HOO | High Office of Oversight |
| HOO | Headquarters Operations Officer (US NRC) |
| HOO | Holding Our Own |
| HOO | Housing Operations Office (various schools) |
| HOO | Home Office Overhead |
| HOO | Hanford Operations Office |