- Oceans Healthcare
- Ochsner Health System
- Ohiohealth
- Ohio State University Health System
- Oklahoma Heart Hospital
- Olathe Health System
- Olmsted Medical Center
- Olympic Medical Center
- One Brooklyn Health System
- Oneida Healthcare
- Optim Healthcare
- Oregon Health and Science University
- Orlando Health
- OSF Healthcare System
- Oswego Health
- OU Health
- Owensboro Health
- Ozarks Community Hospital Health System