Shannon Vyff is an American transhumanist, cryonicist, and author. She is a director of both the Immortality Institute and the Society for Venturism.

Vyff's approaches in promoting transhumanism and cryonics were given exposure when her essay "Confessions of a Proselytizing Immortalist" was published in 2006 as part of the book The Scientific Conquest of Death. Vyff has also been interviewed by the media on subjects pertaining both to her approaches in promoting cryonics to the public at large (especially to children), and her own motivations for becoming a cryonicist.