Gestuno or International Sign Language of the Deaf is a constructed sign language, which the World Congress of the World Federation of the Deaf originally discussed in 1951. The name "Gestuno" is from Italian, meaning "the unity of sign languages." Gestuno is now usually referred to as simply International Sign.

In 1973, a committee created and standardized a system of international signs. They tried to choose the most understandable and inoffensive signs from diverse sign languages to make the language easy to learn. The commission published a book (ISBN 0950418706) with about 1500 signs. Gestuno does not have a concrete grammar, so some say that it is not a real language, rather a vocabulary. Instead of one specific grammar, any sign language grammar can be used.

International Sign is mainly used to communicate at large gatherings of the Deaf from different countries. Many Deaf people use International Sign at the Deaflympic Games and at other international Deaf conferences, such as the World Federation of Deaf convention and the Deaf Way conference.

See also: Signuno