| Abbreviation | Definition |
|---|---|
| OOQ | Occupational Outlook Quarterly |
| OOR | Occupational Outlook Report |
| OP | Official Publication |
| OPA | Children's Online Privacy Protection Act of 1998 |
| OPA | Office of Population Affairs (Department of Health and Human Services) |
| OPA | Office of Price Administration |
| OPA | Other Procurement, Army |
| OPAP | Office of Patent Application Processing |
| OPB | Office of Planning and Budget |
| OPC | Objective Performance Criteria |
| OPE | Office of Postsecondary Education |
| OPE | Outline Of Political Economy |
| OPF | OutPost of Freedom |
| OPH | Office of Public Health |
| OPHG | Office of Public Health Genomics |
| OPHS | Office of Public Health and Science |
| OPIA | Office of Public and Intergovernmental Affairs |
| OPIC | Office of Pesticide Information and Coordination |
| OPIC | Overseas Private Investment Corporation |
| OPL | Oil Prospecting Licence |