| Abbreviation | Definition |
|---|---|
| OT | Over Time |
| OT3 | One True 3-some (Threesome) |
| OTA | Off-season Team Activities |
| OTA | Organized Team Activities |
| OTB | Off The Board |
| OTB | Off Track Betting |
| OTB | Over The Bars |
| OTC | Olympic Training Center |
| OTC | On The Clock |
| OTC | Other Tennis Club |
| OTG | Over The Glasses ski goggles |
| OTL | Outside Time Limit |
| OTL | Over-The-Line Tournament |
| OTN | Ontario Trail Network |
| OTNC | Optimisation des transports de Nouvelle Calédonie |
| OTP | Off The Path |
| OTP | Olympic Trial Participant |
| OTP | Out To Practice |
| OTR | Oval Track Racing |
| OTRA | Ontario Trail Riders Association Inc. |