TUI AG (Touristik Union International) (ISIN: DE000TUAG000) is a German based company. Until 2001 it was an industrial and transportation company named Preussag AG, which in the mid-1990s decided to reinvent itself as a tourism, shipping, and logistics company. It sold off many of its industrial concerns and purchased several major travel and transportation firms.

Today it is one of the world's largest tourist firms with interests across Europe. It owns travel agents, hotels, airlines, cruise ships, retail stores, and container ships. Major subsidiaries include TUI AG Airlines, the largest holiday fleet in Europe. Its common brand TUIfly encompasses 7 airlines. TUI AG is also one of the world's largest shipping companies, having its logistics activities bundled within Hapag-Lloyd AG and concentrated on the highly profitable shipping sector.

Some data of TUI:

• approx. 3,500 travel agencies
• 79 tour operator in 18 countries
• over 120 aircraft
• 37 incoming agencies in 31 countries
• 12 hotel brand in 28 countries with 285 hotels and around 163,000 beds
• 10 cruise liners