The Soyombo symbol (Mongolian: Соёмбо, ᠰᠣᠶᠤᠮᠪᠤ from Sanskrit: svayambhu) is a special character in the Soyombo alphabet invented by Zanabazar in 1686. The name Soyombo is derived from Sanskrit svayambhu self-created. It serves as a national symbol of Mongolia, to be found on the Flag of Mongolia, the Emblem of Mongolia, and on many other official documents.

In the Soyombo alphabet, the two variations of the Soyombo symbol are used to mark the start and end of a text. It is thought to be possible that the symbol itself may predate the script.