| OPST | Ocean Pines Swim Team 
| Others |
| OPST | Office for Policy Security and Technology
| Others |
| OPST | Office of Professional Standards and Training
| Others |
| OPST | Olympic Peninsula Skagit Tactics
| Others |
| OPST | Olympic Peninsula Skagit Techniques
| Others |
| OPST | Online Panel Site Tool
| Others |
| OPST | Optical Packet Switch and Transport
| Others |
| OPST | Optical Packet Switch Transport
| Others |
| OPST | Orthotic Prosthetic Services Tasmania
| Others |
| OPST | OSSTMM (Open Source Security Testing Methodology Manual) Professional Security Tester
| Others |
| OPST | OSSTMM Professional Security Tester
| Others |