VTT may refer to:
- Vacuum Tower Telescope, a Solar telescope on Tenerife in the Canary Islands.
- Valtion teknillinen tutkimuskeskus Technical Research Centre of Finland
- Valmet (originally Valtion Metallitehtaat) = "State Metalworks"
- Mountain bike, known in French as Vélo tout terrain (VTT)
- Avia Trans Air Transport, an airline from Sudan (IATA code VTT)
- WebVTT, a timed text format