| Oberlin Project for Unified Systems | Academic & Science |
| Online Pathway for University Students | Academic & Science |
| Officer Program for Undergraduate Students | Academic & Science |
| Online Publications University of Stuttgart | Academic & Science |
| Open Portal to University Scholarship | Academic & Science |
| Operational Pipeline Unified Systems | Business |
| Online Payroll Update System | Business |
| Optimising Public Understanding of Science | Community |
| Open Platform for Unlimited Signification | Computer Hardware |
| Online Processing User Service | Computing |
| Optical Prism Uniformity System | Computing |
| Optimized Power Usage Solution | Computing |
| Online Positioning User Service | Earth Science |
| Oscillating Pick Up System | Electronics |
| Older People Up to Something | General |
| Outstanding People United to Sing | General |
| Offering Perspective Using Storytelling | General |
| Online Publikationsverbund Universität Stuttgart | General |
| Organization for Paranormal Understanding and Support | General |
| Octal Program Updating System | General |
| One Point Universal System | General |
| Observations of Persistent Upwelling Systems | General |
| Operation to Prevent Unwanted Species | General |
| Outer Planet U Search | General |
| Oscillating Pick-Up Ignition System | General |
| Outdoor Places Unusual Spaces | General |
| Offender Population United System | Governmental |
| Operation United States | Governmental |
| Oss/podps (observation Support System/post-observation Data Processing System) Unified System | Military and Defence |
