TTO may refer to:

• Time-trade-off
• Trinidad and Tobago, by ISO 3166-1 alpha-3 and IOC codes
• Tactical Technology Office, a division of DARPA
• Technology Transfer Office
• Toontown Online, massively multiplayer online role-playing game by Disney
• Transtrachreal oxygen, as used during Jet ventilation
• Trailing throttle oversteer, also known as lift-off oversteer
• Twist-to-open razor, a type of safety razor (see mention under Gillette (brand))
• Triple tibial osteotomy