PTU may refer to:
- Police Tactical Unit (disambiguation), specialist units of various police forces
- Professionalno-Tehnicheskoye Uchilische, Russian for vocational technical school
- Propylthiouracil, a drug used in the treatment of hyperthyroidism
- PTU (film), a 2003 Hong Kong film
- PTU 2, see Tactical Unit (film series)
- Punjab Technical University, at Jalandhar, Punjab, India
- Hong Kong Professional Teachers' Union
- Power transfer unit, a device used on aircraft to transfer power from one hydraulic system to another, in case one of them were to fail
- Pyay Technological University, a Burmese university located in Pyay
- Podatek od Towarów i Usług, abbreviation in Polish for Value added tax
- Phenylthiourea, an alternate name for phenylthiocarbamide, an organosulfur thiourea containing a phenyl ring
- Paroxysmal tonic upgaze, a rare and distinctive neuro-ophthalmological syndrome characterized by episodes of sustained upward deviation of the eyes
- Paratroop Training Unit RAAF, a unit of the Royal Australian Air Force during World War II
- Platinum Airport, IATA code for airport in Platinum, Alaska
- Public Transport Union, former name of the Australian Rail Tram and Bus Industry Union