| Optical Research Associates | Academic & Science |
| Owen Richards Architects | Academic & Science |
| Office of Research Administration | Academic & Science |
| Office of Research and Applications | Academic & Science |
| Oral Research Abstracts | Academic & Science |
| Office of Research Affairs | Academic & Science |
| Outdoor Resorts of America | Business |
| Ontario Rifle Association | Business |
| Ora Capital | Business |
| Aura Minerals Incorporated | Business |
| Operational Readiness Assessment | Business |
| Oil Recycling Association | Community |
| Ohio Restaurant Association | Community |
| Oregon Resource Association | Community |
| Oscillator, Rectifier, and Amplifier | Computer Hardware |
| or with Accumulator | Computing |
| Oracle | Computing |
| Output Register A | Computing |
| Parameter File (oracle) | File Type |
| Oberhof Ruhpolding and Antholz | General |
| Organization Risk Analyzer | General |
| Optimized Runtime And Airflow | General |
| Optiwave Refractive Analysis | General |
| Outdoor Refreshment Area | General |
| Oatmeal Red Ale | General |
| Off Road Academy | General |
| Off Road Addict | General |
| Off Road Armoury | General |
| Offroad Riders Association | General |
| Off Road Action | General |
| Off Road Adventures | General |
| Off Road Awards | General |
| On Road Assistance | General |
| Off Roaders Anonymous | General |
| Off Road Assist | General |
| O'Reilly Automotive | General |
| Online Reservation Application | General |
| Online Repository Assistant | General |
| Oceans Reefs And Aquariums | General |
| Orphans Refugees And Aid | General |
| Object Relational Access | General |
| Oceans Reefs Aquariums | General |
| Online Retail Awards | General |
| Organization for the Resolution of Agunot | General |
| Organizational Registration Authority | Governmental |
| Outdoor Recreation Alliance | Governmental |
| Organización Revolucionaria Anarquista | Governmental |
| Office Of Resource Assistance | Governmental |
| Office of Regulatory Affairs | Governmental |
| Open Records Act | Governmental |
| Oramiral | International |
| Organizational Research Analyst | Jobs |
| Operations Research Analyst | Jobs |
| Outer Rhabdomeres Absent | Medical |
| Offshore Risk Assessment | Military and Defence |
| Operational Requirements Analysis | Military and Defence |
| Ormet Railroad | Regional |
| Office of Regional Affairs | Regional |
| Oran, Santa Ana, Argentina | Regional |
| Ormet Railroad Corporation | Regional |
| Ontario Racing Association | Sports |
