TTA may refer to

• Tan Tan Airport, Morocco, IATA code
• Teacher Training Agency, former name of the Training and Development Agency for Schools, England
• Technical Theatre Awards, UK
• Terran Trade Authority, the setting for a series of science-fiction books
• Tetradecylthioacetic acid, a fatty acid
• The Three Amigonauts, a cartoon series
• The Tough Alliance, a synthpop duo from Sweden
• Thenoyltrifluoroacetone, a chelating agent also commonly known as TTFA
• Tibial tuberosity advancement, a knee operation in dogs
• Tiny Toon Adventures, an animated television series
• Toledo Technology Academy, a public high school in Toledo, Ohio, US
• Tomorrowland Transit Authority PeopleMover, in Tomorrowland in Magic Kingdom at Walt Disney World Resort in Orlando, Florida
• Total TEU Allowance
• Tramway Touristique de l'Aisne, a tourist tramway in Belgium
• Transport Ticketing Authority, Victoria, Australia
• Transport triggered architecture, computer processor design
• Triangle Transit Authority, a regional transit service in North Carolina, US
• Tri-State Transit Authority, a transit service in the Huntington, West Virginia, US area
• Ṭa (Indic), the eleventh consonant of Indic abugidas
• Transfusion-transmitted anaplasmosis, a human bacterial infection caused by blood transfusion
• TTA – Racing Elite League, a Swedish touring car championship
• TTA, a codon for the amino acid Leucine