| OPPA | Office of Policy and Practice Alignment 
| Others |
| OPPA | Office of Projects Planning and Analysis
| Others |
| OPPA | Ohio Promotional Product Association
| Others |
| OPPA | Ohio Promotional Products Association
| Others |
| OPPA | Ohio Psychiatric Physicians Association
| Others |
| OPPA | Online Privacy Protection Act
| Others |
| OPPA | Online Privacy Protection Act of 2003
| Others |
| OPPA | Ontario Political Payoff Act
| Others |
| OPPA | Ontario Provincial Police Association
| Others |
| OPPA | Operation Plan Package Appraisal
| Others |
| OPPA | Oregon Professional Photographers Association
| Others |
| OPPA | Oregon Public Purchasing Association
| Others |