The International Air Transport Association is an international industry trade group of airlines headquartered in Montreal, Quebec, Canada, where the International Civil Aviation Organisation also happens to be headquartered, even though they are different entities. The main objective of the organization is to assist airline companies to achieve lawful competition and uniformity in prices.

IATA was formed in April 1945, in Havana, Cuba. It is the successor to the International Air Traffic Association, founded in The Hague in 1919, the year of the world's first international scheduled services. At its founding, IATA had 57 members from 31 nations, mostly in Europe and North America. Today it has over 240 members from more than 140 nations in every part of the globe.

For fare calculations IATA has divided the world in three regions:

1. South, Central and North America.
2. Europe, Middle East and Africa. IATA Europe includes the geographical Europe and Morocco, Algeria and Tunisia.
3. Asia, Australia, New Zealand and the islands of the Pacific Ocean.

To this end, airlines have been granted a special exemption by each of the main regulatory authorities in the world to consult prices with each other through this body. However, the organisation has been accused of acting as a cartel, and many low cost carriers are not full IATA members. The European Union's competition authorities are currently investigating the body. In 2005, Neelie Kroes, the European Commissioner for Competition, made a proposal to lift the exception to consult prices. In July 2006, the United States Department of Transportation also proposed to withdraw antitrust immunity . IATA teamed with SITA for an electronic ticketing solution .

IATA assigns 3-letter IATA Airport Codes and 2-letter IATA airline designators, which are commonly used worldwide. ICAO also assigns airport and airline codes. For Rail&Fly systems, IATA also assigns IATA train station codes. For delay codes, IATA assigns IATA Delay Codes.

IATA is pivotal in the worldwide accreditation of travel agents with exception of the U.S., where this is done by the Airlines Reporting Corporation. Permission to sell airline tickets from the participating carriers is achieved through national member organizations.

They also regulate the shipping of dangerous goods and publish the IATA Dangerous Goods Regulations manual, a globally accepted field source reference for airlines shipping of hazardous materials.