| OH&S | Occupational Health & Safety 
| Others |
| OHS | Oakdale High School
| Others |
| OHS | Oakland High School
| Others |
| OHS | Oakleaf High School
| Others |
| OHS | Oakley High School
| Others |
| OHS | Oakmont High School
| Others |
| OHS | Oakwood High School
| Others |
| OHS | Obesity Hyperlipidemia Syndrome
| Others |
| OHS | Obesity Hypoventilation Syndrome
| Others |
| OHS | Occipital Horn Syndrome
| Others |
| OHS | Occupational Health and Safety
| Others |
| OHS | Occupational Health Safety
| Others |
| OHS | Occupational Health Service
| Others |
| OHS | Occupational Health Standards
| Others |
| OHS | Occupational Health, Safety
| Others |
| OHS | Oceana High
| Others |
| OHS | Oceana High School
| Others |
| OHS | Oceanside High School
| Others |
| OHS | Oconomowoc High School
| Others |
| OHS | Office of Head Start
| Others |
| OHS | Office of Health Strategy
| Others |
| OHS | Office of Hearing Services
| Others |
| OHS | Office of Highway Safety
| Others |
| OHS | Office of Homeland Security
| Others |
| OHS | Ohio Historical Society
| Others |
| OHS | Oklahoma Historical Society
| Others |
| OHS | Olentangy High School
| Others |
| OHS | Olympia High School
| Others |
| OHS | Olympic High School, Charlotte, North Carolina
| Others |
| OHS | One Hand Spey
| Others |
| OHS | One Hip Sista
| Others |
| OHS | One Hour Sonic
| Others |
| OHS | Onehunga High School
| Others |
| OHS | Online Help System
| Others |
| OHS | Online High School
| Others |
| OHS | Ontario High School
| Others |
| OHS | Ooltewah High School
| Others |
| OHS | Open Hardware Summit
| Others |
| OHS | Open Heart Surgery
| Others |
| OHS | Open Hyperdocument System
| Others |
| OHS | Open Hypermedia Systems
| Others |
| OHS | Open Hypertext System
| Others |
| OHS | Operational Health Standards
| Others |
| OHS | Oracle HTTP Server
| Others |
| OHS | Oral Health Sciences
| Others |
| OHS | Oral Health Section
| Others |
| OHS | Oral Hydration Solution
| Others |
| OHS | Orange High School
| Others |
| OHS | Ordinary Human Spirit
| Others |
| OHS | Oregon Health Services
| Others |
| OHS | Oregon Historical Society
| Others |
| OHS | Oregon Humane Society
| Others |
| OHS | Orem High School
| Others |
| OHS | Organ Historical Society
| Others |
| OHS | Oromocto High School
| Others |
| OHS | Oroville High School
| Others |
| OHS | Osbourn High School
| Others |
| OHS | Osceola High School
| Others |
| OHS | Ossining High School
| Others |
| OHS | Oswego High School
| Others |
| OHS | Ottawa High School
| Others |
| OHS | Outback H6 Special
| Others |
| OHS | Outbound History (Bink/+)
| Others |
| OHS | Ovarian Hyperstimulation Syndrome
| Others |
| OHS | Overhills High School
| Others |
| OHS | Overland High School
| Others |
| OHS | Overlapping hard spheres
| Others |
| OHS | Oviedo High School
| Others |
| OHS | Owensboro High School
| Others |
| OHS | Oxford High School
| Others |
| OHS | Oxford Hip Score
| Others |
| OHS | Oxnard High School
| Others |