ADA

ADA or AdA may refer to:

Law

 * Airline Deregulation Act, a 1978 US law removing governmental control from commercial aviation
 * Americans with Disabilities Act of 1990, a US law that prohibits discrimination on the basis of disability
 * Antideficiency Act, a US law that prohibits the federal government from incurring debts not authorized by Congress
 * Assistant district attorney, a US government position

Businesses

 * Aerolínea de Antioquia, a Colombian Airline
 * Alternative Distribution Alliance, a music distributor owned by Warner Music Group

Military organizations

 * Aeronautical Development Agency, an agency of India's Ministry of Defence
 * Air Defense Artillery Branch, a branch of the US Army specializing in anti-aircraft weapons
 * Angehöriger der Armee (AdA), a person on active duty in the Swiss Armed Forces
 * Armée de l'Air, the French Air Force

Other organizations

 * Amazon Development Agency, a development agency in Brazil
 * American Decency Association, an advocacy group against pornography
 * American Dental Association
 * American Diabetes Association
 * American Dietetic Association, the former name of the Academy of Nutrition and Dietetics
 * Americans for Democratic Action, a liberal advocacy organization
 * Amigos dos Amigos, a drug cartel in Rio de Janeiro
 * Association of Drainage Authorities, a membership body for those involved in water level management in the UK
 * Australian Digital Alliance, a copyright advocacy group
 * Australian Dental Association
 * Austrian Development Agency, a development aid agency

Science and technology

 * ADA, a cryptocurrency
 * ADA collider, an electron–positron collider
 * Ada (programming language), a high-level computer programming language
 * Adenosine deaminase, an enzyme involved in purine metabolism
 * Advanced Distribution Automation, an extension of intelligent control over an electrical power grid
 * Analog-to-digital converter (ADA or A/DA), an electronic converter in some electronic devices, often musical
 * Apple Design Awards, an event at the Apple Worldwide Developers Conference
 * Azodicarbonamide, a food additive also used in plastics production
 * ADA (buffer), a chemical buffer in the physiological range

Other uses

 * Adana Şakirpaşa Airport (IATA code)
 * After the Development of Agriculture, a system of counting years
 * Dangme language (ISO 639-2 and ISO 639-3 codes)
 * Asociación Deportiva Agropecuaria, a football club based in the city of Jaén, Cajamarca, Perú