| Abbreviation | Definition |
|---|---|
| OPD | Overton Power District |
| OPE | Oskosh Placement Exhange |
| OPEC | Office of Prevention, Education, and Control |
| OPERS | Ohio Public Employees' Retirement System |
| OPGMB | Ontario Potato Growers' Marketing Board (19761999) (see OPB) |
| OPGMB | Ontario Potato Growers' Marketing Board (1976–1999) (see OPB) |
| OPIC | Office of Public Insurance Counsel |
| OPJ | Office of Peace and Justice |
| OPL | Open and Park Land |
| OPL | Out-migration Population Loss |
| OPM | Office of Policy and Management |
| OPM | Office of Purchasing Management |
| OPOTC | Ohio Peace Officer Training Commission |
| OPPA | Online Privacy Protection Act of 2003 |
| OPPA | Oregon Public Purchasing Association |
| OPPB | Office of Policy, Planning, and Budget |
| OPPB | Oklahoma Pardon and Parole Board |
| OPPM | Office of Policy and Project Management |
| OPPM | Office of Procurement and Property Management |
| OPPM | Operating Policies and Procedures Memorandum |