The commanding officer (CO) or commander, or sometimes, if the incumbent is a
general officer
A general officer is an Officer (armed forces), officer of high rank in the army, armies, and in some nations' air force, air and space forces, marines or naval infantry.
In some usages, the term "general officer" refers to a rank above colone ...
, commanding general (CG), is the officer in
command of a
military unit
Military organization ( AE) or military organisation ( BE) is the structuring of the armed forces of a state so as to offer such military capability as a national defense policy may require. Formal military organization tends to use hiera ...
. The commanding officer has ultimate authority over the unit, and is usually given wide latitude to run the unit as they see fit, within the bounds of
military law. In this respect, commanding officers have significant responsibilities (for example, the
use of force, finances, equipment, the
Geneva Conventions), duties (to higher authority, mission effectiveness,
duty of care
In Tort, tort law, a duty of care is a legal Law of obligations, obligation that is imposed on an individual, requiring adherence to a standard of care, standard of Reasonable person, reasonable care to avoid careless acts that could foreseeab ...
to personnel), and powers (for example, discipline and
punishment
Punishment, commonly, is the imposition of an undesirable or unpleasant outcome upon an individual or group, meted out by an authority—in contexts ranging from child discipline to criminal law—as a deterrent to a particular action or beh ...
of personnel within certain limits of military law).
In some countries, commanding officers may be of any commissioned rank. Usually, there are more officers than command positions available, and time spent in command is generally a key aspect of promotion, so the role of commanding officer is highly valued. The commanding officer is often assisted by an
executive officer
An executive officer is a person who is principally responsible for leading all or part of an organization, although the exact nature of the role varies depending on the organization.
In many militaries and police forces, an executive officer ...
(XO) or
second-in-command (2i/c), who handles personnel and day-to-day matters, and a
senior enlisted advisor. Larger units may also have
staff officers responsible for various responsibilities.
Commonwealth
Army and Royal Marines
In the
British Army
The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...
,
Royal Marines
The Royal Marines provide the United Kingdom's amphibious warfare, amphibious special operations capable commando force, one of the :Fighting Arms of the Royal Navy, five fighting arms of the Royal Navy, a Company (military unit), company str ...
, and many other
Commonwealth military and
paramilitary
A paramilitary is a military that is not a part of a country's official or legitimate armed forces. The Oxford English Dictionary traces the use of the term "paramilitary" as far back as 1934.
Overview
Though a paramilitary is, by definiti ...
organisations, the commanding officer of a unit is appointed. Thus the office of CO is an appointment.
The appointment of commanding officer is exclusive to commanders of major units (
regiment
A regiment is a military unit. Its role and size varies markedly, depending on the country, military service, service, or administrative corps, specialisation.
In Middle Ages, Medieval Europe, the term "regiment" denoted any large body of l ...
s,
battalion
A battalion is a military unit, typically consisting of up to one thousand soldiers. A battalion is commanded by a lieutenant colonel and subdivided into several Company (military unit), companies, each typically commanded by a Major (rank), ...
s and similar sized units). It is customary for a commanding officer to hold the rank of
lieutenant colonel, and they are usually referred to within the unit simply as "the colonel" or the CO. "The colonel" may also refer to the holder of an honorary appointment of a senior officer who oversees the non-operational affairs of a regiment. However, the rank of the appointment holder and the holder's appointment are separate. That is, not all lieutenant colonels are COs, and although most COs are lieutenant colonels, that is not a requirement of the appointment.
Sub-units and minor units (
companies
A company, abbreviated as co., is a legal entity representing an association of legal people, whether natural, juridical or a mixture of both, with a specific objective. Company members share a common purpose and unite to achieve specifi ...
,
squadrons and
batteries) and formations (brigades, divisions, corps and armies) do not have a commanding officer. The officer in command of a minor unit holds the appointment of officer commanding (OC). Higher formations have a commander (e.g. brigade commander) or a
general officer commanding (GOC). Area commands have a commander-in-chief (e.g. C-in-C Land Army, C-in-C British Army of the Rhine). The OC of a sub-unit or minor unit is today customarily a
major (although formerly usually a
captain in infantry companies and often also in cavalry squadrons), although again the rank of the appointment holder and the holder's appointment are separate and independent of each other.
In some cases, independent units smaller than a sub-unit (e.g. a military police platoon that reports directly to a formation such as a brigade) will also have an OC appointed. In these cases, the officer commanding can be a captain or even a lieutenant. The commanders of administrative organisations, such as schools or wings, may also be designated officers commanding or commanders.
Appointments such as CO and OC may have specific powers associated with them. For example, they may have statutory powers to promote soldiers or to deal with certain disciplinary offences and award certain punishments. The CO of a unit may have the power to sentence an offender to 28 days' detention, whereas the OC of a sub-unit may have the power to sentence an offender to three days' restriction of privileges.
Commanders of units smaller than sub-units (e.g.
platoon
A platoon is a Military organization, military unit typically composed of two to four squads, Section (military unit), sections, or patrols. Platoon organization varies depending on the country and the Military branch, branch, but a platoon can ...
s,
troops and
sections) are not specific appointments and officers or NCOs who fill those positions are simply referred to as the commander or leader (e.g. platoon commander, troop leader, section commander/leader, etc.).
Air force
In the
Royal Air Force
The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
, the title of commanding officer is reserved for station commanders or commanders of independent units, including flying squadrons. As with the British Army, the post of a commander of a lesser unit such as an administrative
wing
A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...
,
squadron or
flight
Flight or flying is the motion (physics), motion of an Physical object, object through an atmosphere, or through the vacuum of Outer space, space, without contacting any planetary surface. This can be achieved by generating aerodynamic lift ass ...
is referred to as the officer commanding (OC).
Navy
In the
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
and many others, commanding officer is the official title of the commander of any ship, unit or installation. However, they are referred to as "the captain" no matter what their actual rank, or informally as
"skipper" or even "boss".
United States

In the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, the status of commanding officer is duly applied to all commissioned officers who hold lawful command over a military unit, ship, or installation.
Army
The commanding officer of a
company
A company, abbreviated as co., is a Legal personality, legal entity representing an association of legal people, whether Natural person, natural, Juridical person, juridical or a mixture of both, with a specific objective. Company members ...
, usually a
captain, is referred to as the
company commander (or the
battery/troop commander for
artillery
Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...
/
cavalry
Historically, cavalry (from the French word ''cavalerie'', itself derived from ''cheval'' meaning "horse") are groups of soldiers or warriors who Horses in warfare, fight mounted on horseback. Until the 20th century, cavalry were the most mob ...
) units. The commanding officer of a
battalion
A battalion is a military unit, typically consisting of up to one thousand soldiers. A battalion is commanded by a lieutenant colonel and subdivided into several Company (military unit), companies, each typically commanded by a Major (rank), ...
(or
squadron of
cavalry/armored cavalry) is usually a
lieutenant colonel. The commanding officer of a
brigade
A brigade is a major tactical military unit, military formation that typically comprises three to six battalions plus supporting elements. It is roughly equivalent to an enlarged or reinforced regiment. Two or more brigades may constitute ...
, a
colonel
Colonel ( ; abbreviated as Col., Col, or COL) is a senior military Officer (armed forces), officer rank used in many countries. It is also used in some police forces and paramilitary organizations.
In the 17th, 18th, and 19th centuries, a colon ...
, is the
brigade commander. At the
division level and higher, however, the commanding officer is referred to as the
commanding general, as these officers hold
general officer
A general officer is an Officer (armed forces), officer of high rank in the army, armies, and in some nations' air force, air and space forces, marines or naval infantry.
In some usages, the term "general officer" refers to a rank above colone ...
rank.
Warrant officers in the
United States Armed Forces
The United States Armed Forces are the Military, military forces of the United States. U.S. United States Code, federal law names six armed forces: the United States Army, Army, United States Marine Corps, Marine Corps, United States Navy, Na ...
are single career-track officers that can, and occasionally do, hold command positions within certain specialty units, i.e.
Special Forces
Special forces or special operations forces (SOF) are military units trained to conduct special operations. NATO has defined special operations as "military activities conducted by specially designated, organized, selected, trained and equip ...
and
Army Aviation. However, warrant officers usually do not command if a commissioned officer is present; normally they serve as
executive officer
An executive officer is a person who is principally responsible for leading all or part of an organization, although the exact nature of the role varies depending on the organization.
In many militaries and police forces, an executive officer ...
(
2IC).
Marine Corps

The commanding officer of a
company
A company, abbreviated as co., is a Legal personality, legal entity representing an association of legal people, whether Natural person, natural, Juridical person, juridical or a mixture of both, with a specific objective. Company members ...
, usually a
captain, is referred to as the
company commander or the
battery commander (for
field artillery
Field artillery is a category of mobile artillery used to support army, armies in the field. These weapons are specialized for mobility, tactical proficiency, short range, long range, and extremely long range target engagement.
Until the ear ...
and
low altitude air defense units). The commanding officer of a
battalion
A battalion is a military unit, typically consisting of up to one thousand soldiers. A battalion is commanded by a lieutenant colonel and subdivided into several Company (military unit), companies, each typically commanded by a Major (rank), ...
or a
squadron (
Marine aviation), is usually a
lieutenant colonel. The commanding officer of a
regiment
A regiment is a military unit. Its role and size varies markedly, depending on the country, military service, service, or administrative corps, specialisation.
In Middle Ages, Medieval Europe, the term "regiment" denoted any large body of l ...
,
aviation group, or
Marine Expeditionary Unit (MEU) is a
colonel
Colonel ( ; abbreviated as Col., Col, or COL) is a senior military Officer (armed forces), officer rank used in many countries. It is also used in some police forces and paramilitary organizations.
In the 17th, 18th, and 19th centuries, a colon ...
. At the
Marine Expeditionary Brigade (MEB),
Marine Logistics Group (MLG),
Marine Division (MARDIV),
Marine Aircraft Wing (MAW),
Marine Expeditionary Force (MEF), and
Fleet Marine Force (FMF) levels; however, the commanding officer is referred to as the
commanding general, as these officers hold
general officer
A general officer is an Officer (armed forces), officer of high rank in the army, armies, and in some nations' air force, air and space forces, marines or naval infantry.
In some usages, the term "general officer" refers to a rank above colone ...
rank.
Navy and Coast Guard
In the
United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
and
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and Admiralty law, law enforcement military branch, service branch of the armed forces of the United States. It is one of the country's eight Uniformed services ...
, commanding officer is the official title of the commander of a ship, but they are usually referred to as "
the Captain" regardless of their actual rank: "Any naval officer who commands a ship, submarine or other vessel is addressed by naval custom as 'captain' while aboard in command, regardless of their actual rank."
[America's Navy: Commander Naval Surface Force, U.S. Pacific Fleet: Navy Officer Titles: Captain]
They may be informally referred to as "Skipper", though allowing or forbidding the use of this form of address is the commanding officer's prerogative.
A prospective commanding officer (PCO) is a U.S. Navy officer who has been selected for his/her own command. The term is used in correspondence or in reference to the officer before they assume command of the unit (ship, squadron, unit, etc.).
If the sailor in command of a unit is an enlisted member, rather than a commissioned or
warrant officer
Warrant officer (WO) is a Military rank, rank or category of ranks in the armed forces of many countries. Depending on the country, service, or historical context, warrant officers are sometimes classified as the most junior of the commissioned ...
, he or she is referred to as the "officer in charge" rather than "commanding officer". In the Coast Guard it is common for smaller cutters to be commanded by a
chief petty officer.
Air Force
In the
United States Air Force
The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
, the commanding officer of a unit is similarly referred to as the unit commander, such as
squadron commander,
group commander,
wing
A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...
commander, and so forth. Squadron commanders (the base unit of the United States Air Force) are usually majors or lieutenant colonels. Group commanders (made up of two or more squadrons) are usually colonels, while wing commanders may be colonels (typical wings) or generals (larger wings).
See also
*
Command and control
*
Staff (military)
A military staff or general staff (also referred to as army staff, navy staff, or air staff within the individual services) is a group of officers, enlisted, and civilian staff who serve the commander of a division or other large milit ...
References
{{Military and war
Command and control
Military ranks
Titles