| Acronym | Definition |
|---|
| APO | Army Post Office |
| APO | Army & Air Force Post Office |
| APO | Air Post Office |
| APO | Alpha Phi Omega (fraternity) |
| APO | Advanced Planner and Optimizer (aka Advanced Planning and Optimization; SAP software) |
| APO | Apache Point Observatory (Sunspot, New Mexico) |
| APO | Apogee |
| APO | Apochromatic (optics) |
| APO | Asian Productivity Organization |
| APO | Administrative Protective Order |
| APO | Ausserparlamentarische Opposition (Students' Movement in Germany in the late 1960's) |
| APO | Apoplex |
| APO | Auckland Philharmonia Orchestra |
| APO | Authorized Personnel Only (Alias TV show) |
| APO | Authorized Personnel Only |
| APO | Accountable Property Officer |
| APO | Autopilot-Off (band) |
| APO | Audio Processing Object |
| APO | Acute Pulmonary Edema |
| APO | Application Portfolio Optimization (asset management) |
| APO | Auxiliary Police Officer |
| APO | Advance Purchase Order |
| APO | Armenian Philharmonic Orchestra (Yerevan, Armenia) |
| APO | Application Platform Optimization (Microsoft) |
| APO | Alternative Primatial Oversight |
| APO | Administrative Penalty Order |
| APO | Australian Post Office |
| APO | Aldworth Philharmonic Orchestra (UK) |
| APO | Audit Policy and Oversight (US DoD IG) |
| APO | African Political Organization |
| APO | African People's Organization |
| APO | Asia/Pacific Office |
| APO | afloat pre-positioning operations (US DoD) |
| APO | Apollo Program Office |
| APO | Animal Protection Officer |
| APO | AWIPS Program Office (US DoD) |
| APO | Apprentice Police Officer (various locations) |
| APO | Ares Projects Office |
| APO | Arlington Philharmonic Orchestra (Arlington, MA) |
| APO | ALARA Program Office |
| APO | Application Process Outsourcing |
| APO | Army Procurement Objective |
| APO | Administrative Policy Office |
| APO | Algorithmes Parallèles et Optimisation (French: Parallel Algorithms and Optimization) |
| APO | Atlanta Philharmonic Orchestra (Atlanta, Georgia) |
| APO | Acquisition Project/Program Office(r) |
| APO | Action Print Only |
| APO | Advanced Production Orders |
| APO | Adaptive Planning Option |
| APO | Automated Project Order Form System |
| APO | Asset Placement Optimizer |
| APO | FAA Aviation Policy and Plans Office |
| APO | Optical Answer Print |
| APO | ASAS Project Office |
| APO | Anaesthesia Paramedical Officer |
| APO | Austin Philharmonic Orchestra (Austin, TX) |
| APO | Annual Program Objective |
| APO | Assemble Per Order |
| APO | Action Pilote Orientation (French: Pilot Action Orientation) |
| APO | Assualting a Police Officer (crime) |
| APO | Assistant Program Officer (various organizations) |
| APO | Asset Project Office (US Coast Guard) |