"Tat" may refer to:
*TAT (band) London, UK
*The "Tats", an Iranian ethnic group from the Caucasus.
*"Tat" is the Southwestern Indo-Iranian language used by a Jewish people of the Caucasus Mountains and Israel (Judeo-Tat) and a Muslim people in Azerbaijan (Muslim Tat).
*"TAT" stands for transatlantic telephone. The first transatlantic telephone cable (TAT-1) was laid in 1956. It had the capacity to carry 35 conversations over 64 kbit/s channels.
*"Tat" is also a term, found particularly in England, referring to anything which appears shabby, cheap, and tasteless.
*"Tat" is an 86-101 residue ''t''rans-''a''c''t''ing regulatory protein (9-11 kDa) produced early in HIV-1 infection whose primary role is in regulating productive and processive transcription from the HIV-1 long terminal repeat (LTR).
*"TAT" stands for Thematic apperception test, a projective test used in psychology.
*"Tat" is also slang for a tattoo.
*"TAT" also stands for Tourist Authority of Thailand, the well respected, government run, tourist authority in Thailand which promotes tourism in that country and aims to protect travellers from being conned my more unscrupulous agents.