- ABO stands for Abonnement (German: Subscription)
- ABO stands for Abortion
- ABO stands for Aboriginal
- ABO stands for Anybody but Obama (politics)
- ABO stands for Amway Business Owner
- ABO stands for Accumulated Benefit Obligation
- ABO stands for Accumulated Benefit Obligation (pension plan accounting)
- ABO stands for American Board of Ophthalmology
- ABO stands for American Board of Opticianry (Springfield, VA)
- ABO stands for Algal Biomass Organization (Preston, MN)
- ABO stands for American Board of Orthodontics
- ABO stands for Associated Builders and Owners
- ABO stands for American Board of Otolaryngology
- ABO stands for Association of British Orchestras
- ABO stands for Amsterdam Baroque Orchestra
- ABO stands for Alaska Bird Observatory
- ABO stands for Aviators Breathing Oxygen
- ABO stands for Army Budget Office
- ABO stands for Air Base Operability
- ABO stands for American Board of Opticians
- ABO stands for Agents of Biological Origin
- ABO stands for Accelerated Bookbuilt Offering (investing)
- ABO stands for Automated Box Office (American Multi-Cinema, Inc.)
- ABO stands for Admin Base Objects (Microsoft IIS)
- ABO stands for Air-Breathing Organ (fish biology)
- ABO stands for Association des Bibliotechniciens de l’Ontario
- ABO stands for Antibodies Blood Group
- ABO stands for Atlanta Baroque Orchestra (Atlanta, Georgia)
- ABO stands for Access Basing Overflight (UK)
- ABO stands for Adiabatic Born-Oppenheimer
- ABO stands for Annular Beam Oscillator
- ABO stands for Arbitration Out
- ABO stands for Airborne Order
- ABO stands for Advanced Byte-Oriented
- ABO stands for Absent Bed Occupancy
- ABO stands for Asociación Benedictina Olivetana Centro Educacional (Olivetana Benedictine Association Educational Center, Guatemala)
- ABO stands for Antibonding Bond Orbital
- ABO stands for Across Border Operations
ABO