- BAO stands for Batman: Arkham Origins (gaming)
- BAO stands for Baryon Acoustic Oscillations (cosmology)
- BAO stands for Business Analytics and Optimization (IBM)
- BAO stands for Basal Acid Output (medical test)
- BAO stands for Business Analyst Online (software)
- BAO stands for Bundesabgabenordnung (Austria)
- BAO stands for Bouche à Oreille (French: Word of Mouth)
- BAO stands for Brussels Agentschap voor de Onderneming (Dutch: Brussels Enterprise Agency; Brussels, Belgium)
- BAO stands for Behavior Analyst Online (online scientific journals)
- BAO stands for Bilateral Affairs Officer (US DoD)
- BAO stands for Boulder Atmospheric Observatory
- BAO stands for Birmingham AIDS Outreach
- BAO stands for Bloc Américaniste Occidentaliste (French: American Western Bloc)
- BAO stands for Bachelor of Obstetrics
- BAO stands for Bomb Appraisal Officer (US TSA)
- BAO stands for Boeing Aerospace Operations
- BAO stands for Bruce Artwick Organisation
- BAO stands for Best Available Option
- BAO stands for Branch Artery Occlusion
- BAO stands for Bachelor of the Arts of Obstetrics (UK)
- BAO stands for Battalion Ammunition Officer (US Army)
- BAO stands for Baikal Astrophysical Observatory (Listvyanka, Russia)
- BAO stands for Best Atomic Orbital
- BAO stands for Breathing Apparatus Operator (safety)
- BAO stands for Bear Artists Online (est. 2008)
- BAO stands for 2,5-Bis-4-Aminophenyl-1,3,4-Oxadiazole (chemistry)
- BAO stands for Burlington Area Office
- BAO stands for Business Administration Officer Committees
BAO