- Opus
- Oracle
- Oregon Association for Home Care
- Organization of Nurse Leaders of Massachusetts & Rhode Island
- Orlando Health
- Orthomed Appliance Inc.
- Osborne Home Care Group
- Oscar Health
- OSF Home Care Services
- OSHA
- OSU
- Oswego Health Home Care
- Oswego Home Health Care
- Our Lady of the Lake Regional Medical Center
- Overture Home Care
- Owens & Minor
- Oxford HealthCare