Commandant is a military or police title or rank and can mean any of the following:

• The commander of certain military corps and services, such as the Commandant of the Marine Corps and the Commandant of the Coast Guard in the United States or the Commandant of the (now obsolete) Women's Royal Naval Service in the United Kingdom.
• The commander of a military or police training installation such as a military academy or police academy.
• In some military organisations, the commander of a headquarters unit.
• In line with the two meanings above, a person responsible for the internal workings, especially internal security of a military installation, responsible only to its commanding officer.
• The commander of a military prison or similar penal installation, such as a concentration camp.
• The highest military authority in a town and adjacent area in non-combat area, mainly responsible for the coordination of the depots and training centers.
• A French rank, of the French Army, corresponding to Major. The rank is also used in other militaries and police forces, to include the Irish Army.
• In the British Army, between 1922 and 1928, a Colonel-Commandant was an appointment held by senior colonels, later replaced by the rank of Brigadier.
• In the British Army, the Colonel-Commandant is the honorary commander of some corps, usually a member of the Royal Family or a senior or retired general.
• In the Irish army, a rank below lieutenant-colonel and above captain, equivalent to major in other armies

Military ranks | Police ranks