| Office Procedures Reinforcement | Business |
| Overly Priced Rooms | Business |
| Overflow Press Room | Community |
| Old Parish Records | Community |
| Old Parochial Registers | Community |
| Oakland Parks and Recreation | Community |
| Operator/Operate/Operation | Computing |
| Online Prompt Recognition | Computing |
| Official Pattern Release | Computing |
| Office Password Recovery | Computing |
| Out Pulse Rule | Computing |
| On Page Rank | Computing |
| Original Product Resolution | General |
| Office of Parental Representation | General |
| Operation Portal Recon | General |
| Ordering Prescribing Referring | General |
| Off Peak Return | General |
| Offshore Passage Raft | General |
| Office of Professional Responsibilities | General |
| Ordering Prescribing and Referring | General |
| Overnight Policy Rate | General |
| Operating Performance Report | General |
| Oxford Psychology Research | General |
| Office of Program Research | General |
| Owner Performance Requirements | General |
| Office of Public Records | General |
| Outflow Performance Relationship | General |
| Office of Primary Responsibilities | General |
| Overall Pressure Ratio | General |
| Over Pressure Relief | General |
| Office of Professional Regulation | General |
| Office of Planning and Research | General |
| Outdoor Pursuits and Rentals | General |
| Organizational Psychology Review | General |
| Old Post Road | General |
| Offensive Power Rating | General |
| Operation Photo Rescue | General |
| Overall Player Rating | General |
| Office of Population Research | General |
| Out of Period Revision | General |
| Optimal Performance and Recovery | General |
| Oregon Primate Rescue | General |
| Ohio Professional Registry | General |
| Office of Primary Responsibility | Governmental |
| Official Public Record | Governmental |
| Office of Professional Responsibility | Governmental |
| Officer Performance Report | Governmental |
| Operations Planning Review | Governmental |
| Orbiter/Payload Recorder | Governmental |
| Oxygen Pressure Regulator | Governmental |
| Operational Peer Review | Governmental |
| Official Public Records | Governmental |
| Organisation du Peuple Rodriguais | Governmental |
| Organization of Primary Responsibility | Governmental |
| Oral Phonogram Review | Medical |
| Opioid Pain Reliever | Medical |
| Ottawa & Prescott Railway | Regional |
| Ontario Pacific Railway | Regional |
| Operating Performance Regime | Regional |
| Oregon Pacific Railroad Company | Regional |
| Oregon Pacific Railroad | Regional |
| Old Port Rum | Society & Culture |
| Official Poker Rankings | Sports |
