| OTO | Odero Terni Orlando
| Others |
| OTO | Of Terrestrial Origin
| Others |
| OTO | Office To Office
| Others |
| OTO | Offline To Online
| Others |
| OTO | Old Timers Oirschot
| Others |
| OTO | On Top Of
| Others |
| OTO | Once- Through Oil
| Others |
| OTO | One time offer
| Others |
| OTO | One Time Only
| Others |
| OTO | One-Time-Only
| Others |
| OTO | Online Trust Oracle
| Others |
| OTO | Operations And Training Officer
| Others |
| OTO | Operations Training Officer
| Others |
| OTO | Operator to Operator
| Others |
| OTO | Opportunity To Order
| Others |
| OTO | Oracle Technology Outsourcing
| Others |
| OTO | Ordo Templi Orientis
| Others |
| OTO | Ordos Templi Orientus
| Others |
| OTO | Otology
| Others |
| OTO | Otomian Languages
| Others |
| OTO | Otomobil
| Others |
| OTO | Outflow Tract Obstruction
| Others |
| OTO | Overture To Orchestra
| Others |