NTT may refer to:

• National Native Title Tribunal (NTT), Australian government instrumentality
• NATO countries, as per NATO country code
• New Technology Telescope, a 3.6m telescope at La Silla Observatory, Chile
• New Technology Train, a series of the New York City Subway made from 1999 onwards
• New trade theory, an economic theory
• Niuatoputapu Airport, IATA code
• Nippon Telegraph and Telephone (NTT), a Japanese telecommunications company
  • NTT Docomo, a mobile phone operator, subsidiary of NTT founded in 1991
• Nottinghamshire, county in England, Chapman code
• Number theoretic transform, a mathematical transform
• East Nusa Tenggara, a province of Indonesia known as Nusa Tenggara Timur in Indonesian language.
• non-traditional tincture (heraldry)
• The New Traveller's Tales (NTT) engine, a game engine used for the 2022 video game Lego Star Wars: The Skywalker Saga
• NTT (Uzbek TV channel), an Uzbek television channel