TO

To or to may refer to:

* a grammatical particle used in forming the English verbal infinitive
* .to, the Internet domain country code for Tonga
* To Department, one of the 7 departments of the Sissili Province of Burkina Faso
* Johnnie To, Hong Kong film director and producer
* Nihonto - Japanese word for "sword".
* Teraoctet, a unit of information or computer storage

TO may stand for:
*Toronto, "T" stands for Toronto, and "O" stands for Ontario, the province to which Toronto serves as its capital city.
*Toulouse Olympique, a French rugby league club.
*Thousand Oaks, California
*Tonga, ISO 3166-1 alpha-2 country code
*President Airlines, IATA airline designator
*Takeoff
*Telephone operator
*Internet Relay Chat slang for "takeover"
*A medieval T and O map ("orbis terrae")
*Territorial Defense Forces (TO), part of the armed forces of the former SFR Yugoslavia
*In sports:
**Turnover (disambiguation)
**Time-out (sport)
**Terrell Owens, NFL wide receiver
*JEDEC transistor outline
*Talk.Origins, a Usenet discussion forum
*Tactics Ogre, a Japanese tactical role-playing video game series
*Tantra Online, an online computer game
*"The Outsiders" (novel), a novel by S.E. Hinton
*Thermal oxidizer