| Acronym | Definition |
|---|
| OPIA➣Office of Public Interest Advising (Harvard University) |
| OPIA➣Ontario Printing and Imaging Association |
| OPIA➣Oklahoma Private Investigators Association (est. 1984) |
| OPIA➣Ontario Plumbing Inspectors Association, Inc. (Canada) |
| OPIA➣Optical Precision Instrument Associates |