OT may refer to:
- OffTopic.com, The sixth largest internet message board in the world
- Operational Transformation (OT) an optimistic concurrency control method for group editing
- Aeropelican Air Services IATA airline designator
- overtime
- oblivious transfer
- occupational therapy
- Occupational therapist
- offensive tackle, either of two football positions
- Old Testament
- Old Trafford
- on-topic & off-topic
- Operating Thetan, in Scientology, a spiritual state of a being able to operate free of the encumbrances of the material universe
- operating theatre
- optimality theory
- Organisation Todt, a Third Reich civil and military engineering group
- Oakville Trafalgar High School
- Oberlin Fighting Tigers
- Otago, a region of New Zealand
- O.T. Recordings, a record label
- Open Tibia, Open Tibia Is an Open Source Project That Helps People Making There Own OT.–
- O brněný T ransportér - Czech for Armored Transporter
- OT-62 - Series of tracked armoured vehicles
- OT-64 - Series of 8X8 armoured vehicles
- OT-65 - Series of 4x4 Armoured Cars of Hungarian design similar to the BRDM-1
- OT-810 - Half-track infantry combat vehicle series
See also
- Ot, Mongolian goddess
- Ot (Cyrillic) (Ѿ, ѿ), a letter of the early Cyrillic alphabet
