• A common name or part of a name of numerous species of birds, including:
• Tits, chickadees and titmice of the family Paridae
• Long-tailed tits, of the family Aegithalidae
• Wrentit, of the family Sylviidae
• Tit-babblers, of the family Timaliidae
• Penduline tits, of the family Remizidae
• Bearded Tit, of the family Panuridae
• Tomtit, of the family Petroicidae
• Teat, an alternative word for a nipple
• Female breasts
• Sugar-tit, a pacifier
• A small horse, or an inferior or weedy horse
• Drugs (slang)
• Jacques Tits, a French/Belgian mathematician
• Tits group, named after Jacques Tits
• An idiot
• A sharp or sudden pull; a jerk, tug or twitch (chiefly Scotland)
• Something resembling or held to resemble a tit:
• A shaving left behind on the work after facing on a lathe
• Tokyo Inbred Teachings T.I.T.
• A feature on the bottom of containers formed from injection blow molding
• A small metal part that ejects the finished nails from the bore in nail making

TIT may refer to:

• Trinary digit in the ternary numeral system
• Tarski's indefinability theorem
• Tehran International Tower, a residential tower located in Tehran, Iran
• Turkish Revenge Brigade, Türk İntikam Tugayı, TİT
• Tokyo Institute of Technology, TIT
• Trotters Independent Traders, TIT or T.I.T., a fictional company from the BBC sitcom Only Fools and Horses
• TIT&S, the Technological Institute of Textile & Sciences‎, situated in Bhiwani, State of Haryana in India
• Turbine inlet temperature, a measurement of air temperature at the inlet of a gas turbine or other piece of turbomachinery