Betrayer is someone who has caused a betrayal. It also may refer to:
Books Betrayer (novel), a novel by C. J. Cherryh The Betrayers, Matt Helm spy novel Betrayer, a novel in The Horus Heresy series by Aaron Dembski-Bowden
Films and games Betrayer (film), a 2020 Czech film The Betrayer, a 1921 Australian-New Zealand film Betrayer (video game), a first-person action-adventure video game released in 2014 Music Betrayer (Argentinian band), a female fronted groove metal band from Buenos Aires, Argentina, supplemented by Johan Liiva