| Abbreviation | Definition |
|---|---|
| OGA | One Goofy Asian |
| OGA | Other Goverment Agency |
| OGA | Other Government Agency |
| OGL | Overall Grade Level |
| OGM | Orbit to Ground Missile |
| OGS | Overseas Ground Station |
| OGSMA | Office of Global Situational Maritime Awareness |
| OH | Oral History |
| OHDACA | Overseas Humanitarian, Disaster, and Civic Aid |
| OHDM | Office of Humanitarian Assistance, Disaster Relief, and Mine Action |
| OHEAC | O'Gara- Hess & Eisenhardt Armoring Company |
| OHG | Official Hotel Guide |
| OHIO | Over the Hill In October |
| OHMS | On Her Majesty's Service |
| OHMS | On His Majesty's Service |
| OHNS | Ocupational Health aNd Safety |
| OHQ | Operational HeadQuarters |
| OI | Office of Intelligence (USCS) |
| OI | Operating Instruction |
| OI | Out Of Iraq |