| Acronym | Definition |
|---|
| RO | Radar Operator |
| RO | Radiological Officer |
| RO | Range Only (sonobuoy, AN/SSQ-47) |
| RO | Ranking Officer |
| RO | Record Only |
| RO | Regional Operation (various organizations) |
| RO | Registration Officer |
| RO | Reliability of Operations |
| RO | Remains Open |
| RO | Remote Operations |
| RO | Renewables Obligation (UK) |
| RO | Report Orderly |
| RO | Reportable Occurrence |
| RO | Reporting Officer |
| RO | Required One-Time |
| RO | Requirements Objective |
| RO | Requirements Officer |
| RO | Rescue Officer |
| RO | Reserve Officer |
| RO | Residence Order |
| RO | Resident Office |
| RO | Retired Officer (UK) |
| RO | Revenue Officer |
| RO | Revenue Outturn (UK) |
| RO | Reviewing Official |
| RO | Ride-On (Montgomery County, Maryland transit provider) |
| RO | Risk Officer |
| RO | Romania |
| RO | Rondônia (Brazilian state) |
| RO | Routine Order (Canadian Military) |
| RO | Routing Office (US Navy) |
| RO | Tarom Romanian Air Transport (IATA airline code) |