Prisoner X may refer to:
Placeholder name for prisoners Ben Zygier, held in Ayalon Prison in Israel until his death there in 2010 Ali-Reza Asgari, incorrectly asserted to be Prisoner X by the Tikun Olam blog Avri Elad (died 1993), the "third man" or "X" in the Lavon Affair, held in Ayalon Prison Marcus Klingberg, held from 1983 to 2003 in Israel Prisoner X2, an unidentified prisoner held in Ayalon Prison from about 2004 until 2018 Tomer Eiges, or "Officer X", died in military prison awaiting trial in 2021
Other uses Age of X-Man: Prisoner X, a 2019 comic book, part of the Age of X-Man crossover Prisoner X, a 2015 Canadian film