| Acronym | Definition |
|---|
| OTS | Officer Training School |
| OTS | Office of Thrift Supervision (US Department of the Treasury) |
| OTS | Office of Technology Services |
| OTS | On the Square (various organizations) |
| OTS | Outer Space Treaty (est. 1967; space law; various nations) |
| OTS | Office of Traffic Safety |
| OTS | Options Trading System |
| OTS | On the Side (band) |
| OTS | Organization for Tropical Studies (Costa Rica) |
| OTS | Off-The-Shelf |
| OTS | Open Testing Service |
| OTS | On the Spot |
| OTS | Original Text Service (press communications) |
| OTS | Out of Service (complete system/equipment failure) |
| OTS | On the Scene |
| OTS | One Tight Slap |
| OTS | Ontario Tire Stewardship (Ontario, Canada) |
| OTS | Overseas Trade Statistics (UK) |
| OTS | Over The Shoulder |
| OTS | Opportunity To See |
| OTS | Oncotherapy Science, Inc. (Japan) |
| OTS | Object Based Temporal Scalability |
| OTS | Open Technical Support |
| OTS | over Temperature Shutdown |
| OTS | Open Two Seater |
| OTS | Optical Transport Section |
| OTS | Object Transaction Service |
| OTS | Old Testament Survey |
| OTS | Office of Transportation Services (various locations) |
| OTS | Object Transaction Service (CORBA) |
| OTS | One Time Settlement (legal) |
| OTS | Ontario Thoracic Society (Ontario, Canada) |
| OTS | Open Two Seater (Jaguar) |
| OTS | Optimind Technology Solutions (Philippines) |
| OTS | Optical Transport System (Ciena) |
| OTS | Operator Training Simulator |
| OTS | Occupational Therapy Student |
| OTS | Ordre du Temple Solaire (French: Order of the Solar Temple) |
| OTS | One-Time Source (US DoD) |
| OTS | Octadecyltrichlorosilane |
| OTS | Officers Training School (Mangla, Pakistan) |
| OTS | Office of Toxic Substances |
| OTS | Office of Transport Security (Australia) |
| OTS | Off the Subject |
| OTS | Orbital Test Satellite |
| OTS | Over-The-Side |
| OTS | Otosclerosis |
| OTS | Operator Training System |
| OTS | Order Tracking System |
| OTS | Offer to Settle (law) |
| OTS | Oxford Transport Strategy |
| OTS | Opening Theme Song |
| OTS | Oil Temperature Sensor (automotive engines) |
| OTS | Office of Trial Staff |
| OTS | Open Theme Standard |
| OTS | Oahu Transit Services, Inc. |
| OTS | Open Tech Support |
| OTS | Over The Sofa (artwork) |
| OTS | Oshkosh Transit System |
| OTS | Owensboro Transit System (Kentucky, USA) |
| OTS | Over Target Schedule |
| OTS | Object Telephony Server |
| OTS | Off Tool Sample |
| OTS | Orchestra at Temple Square (Mormon Tabernacle Choir; Salt Lake City, Utah) |
| OTS | Office Telesystem |
| OTS | Occurrence Tracking System |
| OTS | Online Transaction System |
| OTS | Optical Telemetry System |
| OTS | Open Transport Service |
| OTS | Ocean Thermal Structure |
| OTS | Outer Thermal Shield |
| OTS | Operational Test Site |
| OTS | Orbit Transfer System |
| OTS | Open to Sky (architecture) |
| OTS | Ordo Templi Satanas (Satanism) |
| OTS | Operations Testing and Simulations |
| OTS | Orbital Tracking Station |
| OTS | Officers' Tactical School |
| OTS | Omnidirectional Tracking System |
| OTS | OSI Transparent Services |
| OTS | Operator Telephone System (ITU-T) |
| OTS | Ordinary Train Staff |