| Abbreviation | Definition |
|---|---|
| OST | of the Secretary of Transportation |
| OST | Office of Secure Transportation |
| OST | Office of the Secretary of Transportation |
| OST | Old Spanish Trail |
| OSTC | Owen Sound Transportation Company |
| OSV | Oldsmobile Special Vehicle |
| OSV | Opel Safety Vehicle |
| OSV | Open Source Vehicle |
| OSV | OPFOR Surrogate Vehicle |
| OSV | Over Sand Vehicle |
| OT | Office of Transportation |
| OT | Open Transport |
| OT | Outer Tracker |
| OTA | Ontario Trucking Association |
| OTA | On-Time Arrival |
| OTAQ | Office of Transportation and Air Quality |
| OTAT | Office of Transit and Active Transportation |
| OTCC | Ontario Transportation Capital Commission |
| OTD | On Time Delivery |
| OTE | Ontario Transportation Expo |