TSO
- British Rail coach type codes
- Marcos TSO
- TCP segmentation offloading
- Taipei Symphony Orchestra
- Tasmanian Symphony Orchestra
- Technical Standard Order
- Tehran Symphony Orchestra
- The Sims Online
- The Stationery Office
- The Summer Obsession
- Threefold social order
- Time Sharing Option
- Tokyo Symphony Orchestra
- Toledo Symphony Orchestra
- Toronto Symphony Orchestra
- Tourist Standard Open
- Trans-Siberian Orchestra
- Transaero Airlines
- Transmission system operator
- Transportation security officer
- Tresco Heliport
- Trichuris suis
- Tso (disambiguation)
- Tucson Symphony Orchestra