Commander is a military rank which is also sometimes used as a military title depending on the individual customs of a given military service. Commander is also used as a rank or title in some organizations outside of the military, particularly in police and law enforcement.

Commander as a military rank

Commander is a military rank used in many navies and some air forces but is very rarely used as a rank in armies. The rank (originally "Master and Commander") originated in the 18th and early 19th centuries to describe lieutenants that were "captains" of smaller ships such as sloops or brigs. The Royal Navy shortened "Master and Commander" to just "Commander" in 1794.

Royal Navy

A commander in the British Royal Navy is above the rank of lieutenant-commander, below the rank of captain, and is equivalent in rank to a lieutenant colonel in the army. A commander may command a frigate, destroyer, submarine, aviation squadron or shore installation, or may serve on a staff.

Royal Australian Navy

A Commander in the Royal Australian Navy (RAN) is identical in description to a Commander in the British Royal Navy. RAN Chaplains who are Division 1, 2 and 3 (of 5 divisions) have the equivalent rank standing of Commanders but do not wear this rank on their uniform.

Royal Air Force

Since the British Royal Air Force's middle-ranking officers' designations are modelled after the Royal Navy's, the term wing commander is used as a rank and is equivalent to a lieutenant colonel in the army or commander in the navy. The rank is above Squadron Leader and below Group Captain.

In the now defunct Royal Naval Air Service, which amalgamated with the Royal Flying Corps to form the Royal Air Force in 1918, pilots held appointments as well as their normal Royal Navy ranks, and wore insignia appropriate to the appointment instead of the rank. Flight commander wore a star above a lieutenant's two rank stripes, squadron commander wore two stars above two rank stripes (less than eight years' seniority) or two-and-a-half rank stripes (over eight years seniority), and wing commander wore three rank stripes. The rank stripes had the usual Royal Navy curl, and were surmounted by an eagle.

Canadian Navy

main: Commander (Canada)

United States

main: Commander (United States)

British Army

In the British Army, the term "commander" is officially applied to the non-commissioned officer in charge of a section (section commander), vehicle (vehicle commander) or gun (gun commander), to the subaltern or captain commanding a platoon (platoon commander), or to the brigadier commanding a brigade (brigade commander). Other officers commanding units are usually referred to as the Officer Commanding (OC), Commanding Officer (CO), General Officer Commanding (GOC), or General Officer Commanding-in-Chief (GOC-C), depending on rank and position, although the term "commander" may be applied to them informally.