Citadel is an American spy action television series created by Josh Appelbaum, Bryan Oh, and David Weil for Amazon Prime Video, with the Russo brothers acting as executive producers. It stars Richard Madden and Priyanka Chopra as Citadel agents Mason Kane and Nadia Sinh, respectively. Kane discovers a new organization, Manticore, led by Dahlia (Lesley Manville), leading to a bad accident. Eight years later, he is living quietly as Kyle Conroy, with his memory wiped, until an old colleague (Stanley Tucci) needs his help.

With a production budget of US$300 million, the six-episode first season ranks as one of the most expensive television series ever made. The first season premiered on April 28, 2023, with its first two episodes. In March 2023, it was renewed for a second season, with Joe Russo announced to direct all the episodes in the season.

Multiple non-English language spin-off shows have been announced, with settings being in the Italian Alps, India, Spain, and Mexico. The Italian series, Citadel: Diana, premiered October 10, 2024, while the Indian series, Citadel: Honey Bunny, premiered November 7, 2024.