Amadeus IT Group, S.A. (/ˌæməˈdeɪəs aɪ ˈtiː/) is a major Spanish multinational technology company that provides software for the global travel and tourism industry. It is the world's leading provider of travel technology that focus on developing software for airlines, hotels, travel agencies, and other travel-related businesses.

The company is structured around two areas: its global distribution system and its Information Technology business. Amadeus provides search, pricing, booking, ticketing and other processing services in real-time to travel providers and travel agencies through its Amadeus CRS distribution business area. It also offers computer software that automates processes such as reservations, inventory management software and departure control systems. It services customers including airlines, hotels, tour operators, insurers, car rental and railway companies, ferry and cruise lines, travel agencies and individual travellers directly.

Amadeus processed 945 million billable travel transactions in 2011.

The parent company of Amadeus IT Group, holding over 99.7% of the firm, is Amadeus IT Holding S.A. It was listed on the Spanish stock exchanges on 29 April 2010.

Amadeus has central sites in Madrid, Spain (corporate headquarters and marketing), Sophia Antipolis, France (product development), London, UK (product development), Breda, Netherlands (development), Erding, Germany (Data center) and Bangalore, India (product development) as well as regional offices in Bangkok, Buenos Aires, Dubai, Miami, Istanbul, Singapore, and Sydney. At market level, Amadeus maintains customer operations through 173 local Amadeus Commercial Organisations (ACOs) covering 195 countries. The Amadeus group employs 21,500 employees worldwide, and listed in Forbes' list of "The World's Largest Public Companies" as No. 985.

Amadeus was originally created as a neutral global distribution system (GDS) by Air France, Iberia, Lufthansa and SAS in 1987 in order to connect providers' content with travel agencies and consumers in real time. The creation of Amadeus was intended to offer a European alternative to Sabre, an American GDS. The first Amadeus system was built from core reservation system code coming from System One, an American GDS that competed with Sabre but went bankrupt, and a copy of the Air France pricing engine. These systems were respectively running under IBM TPF and Unisys. At the first, the systems were dedicated to airline reservation and centered on the PNR (Passenger Name Record), the passenger's travel file. Gradually the PNR was opened up to additional travel industries (hotels, rail, cars, cruises, ferries, insurance, etc.).

Initially a private partnership, Amadeus went public in October 1999, becoming listed on the Paris, Frankfurt and Madrid stock exchanges. The firm diversified its operations with information technologies (IT) to deliver services beyond sales and reservation functionalities, centered on streamlining the operational and distribution requirements of its customer base.

Since 2004, the company has invested €1 billion in R&D with its technology increasingly using open systems which provide clients with more flexibility and features. As of 2010^[update], 85% of its software portfolio was open system based and it expects by the end of 2016 to have fully migrated away from mainframe-based TPF software.