| Acronym | Definition |
|---|
| ATO | Australian Taxation Office |
| ATO | Alpha Tau Omega |
| ATO | Air Traffic Organization (FAA) |
| ATO | Arab Towns Organization |
| ATO | Ambito Territoriale Ottimale (Italy) |
| ATO | Assemble To Order |
| ATO | Authority to Operate |
| ATO | Air Tasking Order |
| ATO | Atmos Energy Corporation (stock symbol) |
| ATO | Automatic Train Operation (for rail signaling systems) |
| ATO | Abort To Orbit (Shuttle) |
| ATO | Air Transportation Office (Philippines) |
| ATO | Advanced Technology Office (US DARPA) |
| ATO | Approval to Operate |
| ATO | Agency Tender Official (US Army) |
| ATO | Athens Ohio (airport code) |
| ATO | Air Traffic Operations |
| ATO | Army Technology Objective (formerly Science and Technology Objective) |
| ATO | Antimony Trioxide |
| ATO | Asset Turnover |
| ATO | Ammunition Technical Officer |
| ATO | Anti-Terrorism Officer |
| ATO | All Things Organic |
| ATO | Ankara Ticaret Odasi |
| ATO | After the Order (band) |
| ATO | Alternative Trading Organization (fair trade organization) |
| ATO | African Timber Organisation |
| ATO | Afloat Training Organization |
| ATO | Authorization to Offer |
| ATO | Assisted Takeoff |
| ATO | Administrative Time Off |
| ATO | Airport Ticket Office |
| ATO | Airborne Tactical Officer |
| ATO | Area Training Officer |
| ATO | Actual Time Over |
| ATO | Automatic Take Off (dairy industry) |
| ATO | Ankara Tabip Odasi |
| ATO | At Time of Order (purchasing) |
| ATO | Account Take Over |
| ATO | Assist the Officer Foundation (Dallas, Texas USA) |
| ATO | Automatic Turn-On |
| ATO | Alternative Treatment Order |
| ATO | Aircraft Transfer Order |
| ATO | Authorized Time Off |
| ATO | Antarctic Terminal Operations |
| ATO | Area of Tactical Operations |
| ATO | Afghanistan Theater of Operations |
| ATO | Air Tasking Officer |
| ATO | Administrative and Training Officer (Office of Emergency Preparedness) |
| ATO | Achilles Tendon Operation |
| ATO | Address (Complete) Time Out (Telcordia) |
| ATO | Analog Tandem Office |
| ATO | ATCCS Test Office |
| ATO | Atmosphere Over Pressure |
| ATO | Aviation Transportation Officer |
| ATO | Advanced Technology Offerings (OSF) |
| ATO | Advisory Title Officer |
| ATO | Authorized Task Order |
| ATO | Accredited Training Organisation |
| ATO | Austria Ticket Online |