ITT may refer to:

• Infantry-Tank Telephone, a device allowing infantrymen to speak to the occupants of armoured vehicles.

• Intuitionistic type theory, other name of Martin-Löf Type Theory
• Intensional type theory

• ITT Inc. (formerly International Telephone & Telegraph), US
• Invitation to tender for a contract
• ITT Semiconductors

• ITT Technical Institute, US
• Former Institute of Technology, Tallaght, Dublin, Ireland
• Institute of Technology, Tralee, Ireland

• Cousin Itt, of the fictional Addams Family
• "I.T.T (International Thief Thief)", a political screed about ITT Corp. by Fela Kuti

• Insulin tolerance test
• Intention to treat analysis in medicine
• Intermittent testicular torsion

• Individual time trial in bicycle racing