As a noun, Tui may refer to:

• Tu'i (or Tui), a title of nobility in Polynesia and some of Melanesia
• Tui (bird), a bird endemic to New Zealand
• Tui, Galicia, a town in Galicia, Pontevedra, Spain
• Tui (beer), a brand of New Zealand beer produced by Tui Breweries
• Tui Sports, a 1930s New Zealand aircraft
• Tui Awards, New Zealand's annual music industry awards
• Tui, the Moon Spirit, a minor character from the American animated television series Avatar: The Last Airbender
• Tui Regio, a region on Saturn's moon Titan
• HMNZS Tui, the name of two ships that have served in the Royal New Zealand Navy
• Tui (deity), a Chinese goddess of happiness, joy and water
• Tui mine, an abandoned mine in New Zealand

As an acronym, TUI may refer to:

• TUI AG (Touristik Union International), German tour operator
• Text User Interface, a retronym coined after the invention of Graphical User Interfaces, to distinguish them from text-based user interfaces
• Telephone User Interface, a type of Voice User Interface (interaction with computers using voice) applied to telephony technology
• Tangible User Interface, a user interface in which a person interacts with digital information through the physical environment
• Touch User Interface, a computer-pointing technology based upon the sense of touch (haptics)
• Turaif Domestic Airport (IATA code: TUI), a public airport in Turaif, Saudi Arabia
• Teachers' Union of Ireland

de:Tui es:Tui fr:Tui ko:Tui it:TUI nl:Tui pt:Tui (desambiguação) fi:TUI