| Abbreviation | Definition |
|---|---|
| OPEN | Open-Car Pleasure and Entertainment Network |
| OPG | Ontario Power Generation |
| OPHI | Organic Plant Health Inc |
| OPI | Occupational Performance Issue |
| OPI | Odontorium Products Inc |
| OPI | Office Products Inc |
| OPI | Office Products International |
| OPI | Ohio Penal Industries |
| OPI | Ophthalmic Physicians Inc |
| OPI | Optical Phusion Inc |
| OPI | Orthodontal Products Incorporated |
| OPI | Outsource Partners International |
| OPI | Overall Performance Incentive |
| OPIC | Oklahoma Petroleum Information Center |
| OPII | Orient Petroleum International Inc |
| OPKL | Orion Power Khulna Ltd |
| OPL | Offshore Port Limit |
| OPL | Old Princeton Landing |
| OPL | Orwin Products Ltd |
| OPL | Overseas Partners, Ltd. |