| Acronym | Definition |
|---|
| HRO | Housing Referral Office |
| HRO | Hogeschool Rotterdam (The Netherlands) |
| HRO | Rostock (Germany, auto license plate) |
| HRO | Human Resources Outsourcing |
| HRO | Human Resources Office |
| HRO | Human Resource Outsourcing |
| HRO | Human Rights Ordinance |
| HRO | Hampshire Record Office (UK) |
| HRO | Ham Radio Outlet |
| HRO | High-Reliability Organization |
| HRO | Harvard- Radcliffe Orchestra (Cambridge, MA) |
| HRO | Human Rights Organization |
| HRO | Hellenic Railways Organisation (Greece) |
| HRO | Harassment Restraining Order |
| HRO | Historische Rezensionen Online (German: Historical Reviews Online) |
| HRO | Harrison, AR, USA - Boone County (Airport Code) |
| HRO | High Resolution Orthophotography |
| HRO | Hard Rubber Orchestra (band) |
| HRO | Humanitarian Relief Operations |
| HRO | Humanitarian Relief Organization |
| HRO | Hospital Regional de Occidente (Guatemala) |
| HRO | High Risk Operation |
| HRO | Highest Rated Offeror |
| HRO | Honorary Rural Organizer (trade unions) |
| HRO | Hostage Release Operation (NATO) |
| HRO | Holme Roberts & Owen (law firm; now Bryan Cave HRO (Holme Roberts & Owen); various locations |