Alphabetical company index for letter/character "O", page 7 of 24
- Ohio State University
- Ohio State University at Lima
- Ohio State University at Mansfield
- Ohio State University at Marion
- Ohio State University at Newark
- Ohio State University Hospitals
- Ohio University
- Ohio Valley Banc Corp.
- Ohio Valley College
- Ohio Valley General Hospital
- Ohio Valley Medical Center Springfield
- Ohio Valley Medical Center Wheeling
- Ohio Wesleyan University
- Ohiohealth Mansfield Hospital
- Ohiohealth O'Bleness Hospital
- Ohiohealth Shelby Hospital
- Ohr Pharmaceutical Inc.
- Ohsu Hospital and Clinics
- Oi S.A. ADS
- Oil Chem Technologies
- Oil City Area School District
- Oil City Iron Works
- Oil States International Inc.
- Oil-Dri Corp. of America
- Oilsands Quest Inc.
- Oilton School District
- Ojai Unified School District
- Ojai Valley Community Hospital
- Okaloosa County
- Okaloosa School District
- Okanogan County
- Okanogan School District
- Okarche School District
- Okaw Valley CUSD 302
- Okay School District
- Okeechobee County
- Okeechobee School District
- Okeene Municipal Hospital
- Okeene School District
- Okemah School District