| Abbreviation | Definition |
|---|---|
| OPT | Orange Port Terminal Railway |
| OPT | Oregon Professional Technologist |
| OPTCL | Odisha Power Transmission Corporation Limited |
| OPTCL | Orissa Power Transmission Corporation Ltd |
| OPTCL | Orissa Power Transmission Corporation, Limited |
| OPU | Owatonna Public Utilities |
| OPW | Opportunities & Products Warehouse |
| OPWP | Oman Power and Water Procurement Co. |
| OPWR | Ocean Power Corporation |
| OQF | Oldfields Quality Foods |
| OQI | Oilsands Quest Inc |
| OQI | OmegaQuest, Inc. |
| OQM | Oxfordshire Quality Musclebuilding |
| OQR | Oxebridge Quality Resources, Inc. |
| OQR | Oxfordshire Quality Recreation |
| OQSG | Operator Qualifications Solutions Group |
| OQT | OptiQuest Technologies |
| OR | Outdoor Retailer |
| ORA | Outdoor Resorts of America |
| ORC | Organization Resources Counselors, Inc. |