Citadel (disambiguation)

The Citadel may refer to:
 * Citadel (Level) - one of the maps that will ship with Halo 3: ODST.
 * 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.