ATR

ATR may stand for:

* ATR an Italian-French aircraft manufacturer.
* Advanced Telecommunications Research Institute International
* Advanced Test Reactor, a research reactor at the Idaho National Laboratory
* Advanced tongue root
* Air Transport Radio, a size standard for aircraft electronics boxes
* All That Remains, a metalcore band from Massachusetts, United States
* Alpha Tech Release, a very early version of software released to the public for testing
* Americans for Tax Reform, an American lobbyist group
* Answer to reset, the first message of a smart card after reset by a smart card reader
* Anti-tank rifle
* Army Training Regiment in the British Army
* Art Therapist (ATR), denotation for a registered Art Therapist with licensure
* Atari Teenage Riot, a German techno band performing "digital hardcore" music
* Ataxia telangiectasia and Rad3 related, a protein involved in DNA damage repair
* Atmore (Amtrak station), Amtrak station code ATR
* ATR.1 certificate, a customs document used in trade between EU members and Turkey.
* Attenuated total reflectance, a sampling technique used to enable infrared spectroscopy to be carried out directly on samples in the solid state
* Automatic Target Recognition, the ability for an algorithm to recognize targets based on data obtained from sensors
* Autothermal reforming, a natural gas reforming technology
* Average True Range, a market volatility indicator