ABC

• The Alphabet Song, in which the first words are "ABC"
• ABC Glasgow, a music venue in Glasgow.
• ABC Classics, a record label
• Abc notation, a musical notation language
• Another Bad Creation, an R&B/rap group sometimes referred to as ABC

Science

• Advanced Bioimaging Centre, at Samuel Lunenfeld Research Institute
• ATP-binding cassette transporter genes, one of the largest families of genes
• Aneurysmal bone cyst, a lesion
• ABC flow - specific flow in hydrodynamics, supports dynamo
• abc conjecture, an unproven aspect of mathematical number theory.
• The ABC Model of Flower Development, The ABC Model of Flower Development.
• ABC (medical), Airways, breathing, circulation - a term used in cardiopulmonary resuscitation
• ABC Dry Chemical, the most common extinguishing agent in fire extinguishers
• Abortion-breast cancer hypothesis
• Approximate Bayesian Computation

Computer science

• Atanasoff–Berry Computer, one of the first electronic digital computers
• ABC (programming language)
• ABC (stream cipher), a stream cipher algorithm submitted to the eCRYPT project
• ABC (block cipher), a block cipher algorithm by Dieter Schmidt
• ABC 80, ABC 800 etc.. computers, from Dataindustrier AB of Sweden
• Abstract base class, a programming construct supporting abstraction, a key component of object-oriented programming

Places

• ABC countries or ABC Powers: a political term used to refer to Argentina, Brazil and Chile
• ABC Region (also known as ABCD): an industrial area outside of São Paulo
• ABC islands (Alaska): Admiralty Island, Baranof Island, and Chichagof Island
• ABC islands (Lesser Antilles): the islands of Aruba, Bonaire, and Curaçao

Other

• Abstinence, be faithful, use a condom or ABC strategy, a program favored by organizations aiming to defeat AIDS in Africa and those fighting the spread of sexually transmitted diseases
• Anarchist Black Cross, a world-wide anarchist political support organization
• Cuba, cell based resistance organization against Gerardo Machado in 1930s
• ABC (Yet Another BitTorrent Client)
• The A.B.C. Murders, a novel by Agatha Christie
• ABC store, alcoholic beverage control liquor stores
• ABC Stores, a Hawaii-based convenience store chain
• ABC Warehouse, a Michigan-based appliance and electronics chain.
• ABC weapons, Atomic, Biological, Chemical warfare
• Acadian Baptist Center, a Camp and Retreat Center in Eunice, Louisiana
• Acceptable behaviour contract, part of the British ASBO system
• Activity Based Costing, a financial cost allocation method
• Advanced Booking Charter flights
• Aerated Bread Company, a 19th-20th century British bakery and tea room chain
• African Bird Club
• African Black Coalition
• Aggregate base course, a substrate used in construction for road paving
• Air batu campur, a Malaysian shaved ice dessert.
• Airway, Breathing, Circulation
• Alien big cat
• The California Department of Alcoholic Beverage Control
• American Bird Conservancy
• American-born Chinese
• American Bowling Congress
• Appalachian Brewing Company, a brewery in Pennsylvania, USA
• Arab Banking Corporation
• Artificial birth control
• Asian Badminton Confederation
• Association of British Counties
• Atlanta Bread Company, a bakery/café
• Australian Bird Count project of the Royal Australasian Ornithologists Union
• Asian Basketball Confederation, now renamed as FIBA Asia
• All Basotho Convention, Lesotho