| Acronym | Meaning |
| ATO | Aborted Take-Off (aviation) |
| ATO | Administrative and Training Officer (Office of Emergency Preparedness) |
| ATO | Advanced Technology Office (US DARPA) |
| ATO | Afghanistan Theater of Operations |
| ATO | Afloat Training Organization |
| ATO | Agency Tender Official (US Army) |
| ATO | Agricultural Trade Office (Seoul; South Korea) |
| ATO | Air Tasking Officer |
| ATO | Air Tasking Order |
| ATO | Air Traffic Operations |
| ATO | Air Traffic Organization (FAA) |
| ATO | Air Transportation Office (Philippines) |
| ATO | Airborne Tactical Officer |
| ATO | Aircraft Transfer Order |
| ATO | Alternative Treatment Order |
| ATO | Ammunition Technical Officer |
| ATO | Analog Tandem Office |
| ATO | Anti-Terrorism Officer |
| ATO | Anti-Terrorist Operation (Ukraine) |
| ATO | Approval to Operate |
| ATO | Approved Training Organization |
| ATO | Area of Tactical Operations |
| ATO | Area Training Officer |
| ATO | Army Technology Objective (formerly Science and Technology Objective) |
| ATO | Assemble To Order |
| ATO | Assisted Takeoff |
| ATO | ATCCS Test Office |
| ATO | Australian Taxation Office |
| ATO | Authority to Operate |
| ATO | Authorization to Operate |
| ATO | Authorized Time Off |
| ATO | Automatic Turn-On |
| ATO | Aviation Transportation Officer |