| Acronym | Definition |
|---|
| OK | Oklahoma (US postal abbreviation) |
| OK | Okay |
| OK | Oll Korrect (origin of OK meaning Okay) |
| OK | One Kiss |
| OK | Czech Airlines (IATA airline code) |
| OK | OutKast (hip-hop/rap duo) |
| OK | Okanagan (British Columbia, Canada) |
| OK | Over Kill (band) |
| OK | Oozma Kappa (gaming) |
| OK | Orthokeratology (myopia treatment) |
| OK | Ola Kala (Greek: Everything's fine; an origin for the word Okay) |
| OK | Organized Konfusion (rap duo) |
| OK | 0-Kills |
| OK | Organisierte Kriminalitaet (German: organised crime) |
| OK | Zero Killed |
| OK | On Kerosene (India) |
| OK | Old Kinderhook (a nickname for Martin Van Buren) |
| OK | Operatiekamer (Dutch: Operating) |
| OK | Oskar Kokoschka (painter's signature) |
| OK | Order Known (WWI) |
| OK | Obvious Knowledge |
| OK | Outside Knowledge (research company) |
| OK | Ogre Kingdoms (gaming, Warhammer) |
| OK | Occupational Knowledge International |
| OK | Ohne Korrekten (German: Without Correction) |
| OK | Oscillating Klystron |