Citadel (disambiguation)

The Citadel may refer to:
 * Citadel (Level) - One of the Halo 3 DLC maps.
 * Citadel (Covenant) - The Covenant structure used in Halo Wars.
 * Citadel (Forerunner) - The Forerunner structure located on the Ark.
 * Battle of the Citadel - The last major battle to be fought in the Human-Covenant War.
 * The Citadel Skull achievement - Claimed by obtaining the Citadel Skull.