Citizen X or CitizenX may refer to:
- Citizen X, a 1995 American television film
- Citizen X (TV series), a 2011 Egyptian TV series
- Citizen X (video game), a 2002 video game developed by Digital Pictures
- CitizenX, a pseudonym for Glenn Jacobs, mayor of Knox County also known as the WWE wrestler "Kane"
- Citizen X (character), a member of the new Crusaders (D.C. comics) created by S.H.A.D.E.