Businesses and Occupations
- Oji Paper Co. Ltd
- Old Republic International Corp
- Olin Corp
- Olsten Corp
- Olympia & York Developments Ltd.
- OM Group Inc
- Omnicom Group Inc
- Oneida Ltd
- Onex Corp
- Online information services
- Online shopping
- Online transaction processing
- Operant conditioning
- Oracle Corp
- Ore-Ida Foods Inc
- OReilly Automotive Inc
- Organization theory
- Organizational behavior
- Organizational change
- Organizational structure