| Acronym | Definition |
|---|
| ATR | Americans for Tax Reform |
| ATR | Average True Range (financial indicator) |
| ATR | At the Races |
| ATR | Automatic Target Recognition |
| ATR | Attribute |
| ATR | Alton Towers Resort |
| ATR | Ability-to-Repay (lending) |
| ATR | Access to Recovery (US DHHS) |
| ATR | Acceso de Terceros a la Red (Spanish: Third Party Access Network) |
| ATR | Attenuated Total Reflection |
| ATR | Attenuated Total Reflectance |
| ATR | Autothermal Reforming (syngas generation) |
| ATR | Answer to Request |
| ATR | Avions de Transport Regional (turboprop aircrafts) |
| ATR | Atari Teenage Riot (band) |
| ATR | All That Remains (band) |
| ATR | Atlantic Test Range (US Navy) |
| ATR | Atmore (Amtrak station code; Atmore, AL) |
| ATR | Automatic Traffic Recorder |
| ATR | Aft Torpedo Room |
| ATR | Adaptive Transformation |
| ATR | Aerei da Trasporto Regionale (French-Italian aircraft manufacturer; Blagnac, France) |
| ATR | Akademia Techniczno Rolnicza (Polish: University of Technology and Agriculture) |
| ATR | Advanced Telecommunications Research Institute International |
| ATR | Asphalt Tango Records (Germany) |
| ATR | Answer to Reset |
| ATR | Registered Art Therapist |
| ATR | Anthrax Toxin Receptor (proteins) |
| ATR | Advanced Test Reactor |
| ATR | Above the Rim (Reebok) |
| ATR | Air Transportation Regulations (Canada) |
| ATR | Ataxia Telangiectasia and Rad3-related |
| ATR | Agir pour un Tourisme Responsable (French: Acting for Responsible Tourism; tourism association) |
| ATR | Above the Rest |
| ATR | Action Taken Report |
| ATR | Attrition Reserve (US DoD) |
| ATR | Assessment and Test Report (International Electrotechnical Commission) |
| ATR | African Traditional Religion |
| ATR | Air Transport Rack |
| ATR | Achilles Tendon Rupture |
| ATR | Anti-Tank Rifle |
| ATR | Advanced Tongue Root (phonetics) |
| ATR | Articulated Tail Rotor (aviation) |
| ATR | Audio Tape Recorder |
| ATR | Aided Target Recognition |
| ATR | All Terrain Racing |
| ATR | Art Therapist Registered (Art Therapy Credentials Board) |
| ATR | Analog Tape Recorder |
| ATR | Automatic Thrust Restoration (aircraft) |
| ATR | Automatic Terminal Recognition |
| ATR | Alliance for Transportation Research |
| ATR | Annual Traffic Report (various locations) |
| ATR | Agency Technical Review (US DoD) |
| ATR | Autonomous Target Recognition |
| ATR | Accord Type R (Honda Europe) |
| ATR | Acceptance Test Report |
| ATR | All Tech Related (website) |
| ATR | Advance Tax Ruling (South Africa) |
| ATR | A Territory Resource |
| ATR | Action for Tinnitus Research |
| ATR | Advanced Time Report (project management) |
| ATR | Association Technique de la Route (French: Technical Association of the Road) |
| ATR | Authorization to Return |
| ATR | Air Turbo Ramjet |
| ATR | Amicale du Tracteur Renault (French: Friends of Renault Tractor; est. 1997) |
| ATR | Apollo Token Ring |
| ATR | Alternate Trunk Routing |
| ATR | Alaska Trauma Registry |
| ATR | Arizona Trail Riders (Motorcyclists) |
| ATR | Air Turbo Rocket |
| ATR | Against-The-Rule Astigmatism |
| ATR | Above Top of Rail |
| ATR | Acceptance Test Review |
| ATR | All Thread Rod |
| ATR | Austin Trumbull Radio (ARINC) |
| ATR | Air Traffic Requirements |
| ATR | Advanced Tactical Radar |
| ATR | Ambient Temperature Recorder |
| ATR | As They Rise (kiln-fired brick; UK) |
| ATR | Ammunition Transaction Report |
| ATR | Air Transport Rating |
| ATR | Assistance for Trade Reform |
| ATR | American Technology Research, Inc |
| ATR | Authority to Recruit |
| ATR | Air Traffic Regulations |
| ATR | Antitransmit Receive |
| ATR | Aviation Training Relocation (US Air Force and Japanese Air Self Defense Force) |
| ATR | Available to Reserve (manufacturing) |
| ATR | All Terminal Reliability |
| ATR | Awareness, Trial, Repeat |
| ATR | Agency Technical Representative |
| ATR | Answering Time Recorder |
| ATR | Assistant Technical Representative |
| ATR | Agency Telecommunications Representative |
| ATR | Approved Tank Requirements |
| ATR | Admission Temporaire Roulette (Customs Documentation, Turkey) |
| ATR | Augmented Tree-Based Routing |
| ATR | Australian Technology Resources |
| ATR | Agency Telecommunications Request |
| ATR | Annual Technology Report |
| ATR | Airline Transport Rack |
| ATR | Above Threshold Reporting |
| ATR | Aviation Transport Rack |
| ATR | Anti-Terrorism Representative (various companies) |
| ATR | Advice to Receive (electronic payment processing) |
| ATR | Acceptance of TEMPEST Risk |
| ATR | Aerial Target Review |
| ATR | Automatic Trouble Reporting |
| ATR | Applied Tariff Rate |
| ATR | Anti-Theft Request (signal) |
| ATR | Anti-Time Reaction (Star Trek) |
| ATR | Air Transit Route |
| ATR | Automated Transaction Report |
| ATR | Authorized Traffic Request |
| ATR | All Type Racer VW (Volkswagen) Club (French automobile club) |
| ATR | Aviation Electronics Technician Radar and Radar Nav Equipment (US Navy) |
| ATR | Alltech Recycling, Inc (Fort Worth, TX) |
| ATR | Animal Technician, Registered |