| Abbreviation | Definition |
|---|---|
| OOPC | Okitipupa Oil Palm Company |
| OOS | Optics Online Store |
| OOTA | Ohio Occupational Therapy Association, Inc. |
| OOW | Ohio Ordnance Works |
| OPA | Online Pak Ads |
| OPA | Online Publishers Association |
| OPAC | Ontario Property Assessment Corporation |
| OPAL | Olive Plantations of Australia, LTD. |
| OPC | Oglethorpe Power Corp |
| OPC | Oglethorpe Power Corporation |
| OPC | One Person Company |
| OPC | Opel Performance Centre |
| OPCM | Osborne Partners Capital Management |
| OPCO | Ohio Power Company OPCO |
| OPCO | Oppenheimer Company, Inc. |
| OPCO | Oppenheimer & Company, Inc. |
| OPCO | OurPets Company |
| OPCO | OurPet's Company |
| OPE | Orlando Predators Entertainment |
| OPEN | Olympic and Paralympic Employment Network |