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

{{lang|es|Aerolínea de Antioquia}}, a Colombian Airline
Alternative Distribution Alliance, a music distributor owned by Warner Music Group

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
{{lang|de|Angehöriger der Armee}} (AdA), a person on active duty in the Swiss Armed Forces
{{lang|fr|Armée de l'Air}}, the French Air Force

Adaptive Design Association, New York City based non-profit designing and fabricating adaptive devices for disabled persons
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
{{lang|pt|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

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