| OPAS | Oaks Performing Arts Society
| Others |
| OPAS | Obsolete Painful Anal Solution
| Others |
| OPAS | Oconee Performing Arts Society
| Others |
| OPAS | Ocular Pain Assessment Survey
| Others |
| OPAS | Off Power Assisted Steering
| Others |
| OPAS | Ohio Plein Air Society
| Others |
| OPAS | Ohio Pregnancy Assessement Survey
| Others |
| OPAS | Ohio Pregnancy Assessment Survey
| Others |
| OPAS | Olympas Pain Addiction Services
| Others |
| OPAS | Olympas Pain and Addiction Services
| Others |
| OPAS | Olympic Peninsula Audubon Society
| Others |
| OPAS | Online Project Approval System
| Others |
| OPAS | Ontario Plein Air Society
| Others |
| OPAS | Operational Property Asset System
| Others |
| OPAS | Optical Print Alignment System
| Others |
| OPAS | Orchestra Planning and Administration System
| Others |
| OPAS | Oregon Performing Arts Studio
| Others |
| OPAS | Organizational Prior Approval System
| Others |
| OPAS | Ouachita Parish Animal Shelter
| Others |
| OPAS | Outreach Program for Ahwatukee Seniors
| Others |
| OPAS | Overseas Personal Address Service
| Others |
| OPAS | Overseas Programmes Application System
| Others |