A field officer, field-grade officer, or senior officer is an army, Marine, or air force commissioned officer senior in rank to a company officer but junior to a general officer. In most armies this corresponds to the ranks of major, lieutenant colonel and colonel, or their equivalents. Some countries also include brigadier in the definition.
In the Canadian Armed Forces, the equivalent of field officers are senior officers (French: Officiers supérieurs); they include the army and air force ranks of Major, Lieutenant-Colonel, and Colonel, and the naval ranks of Lieutenant-Commander, Commander, and Captain.
In the French Forces, field officers are called officiers supérieurs (Senior Officers). There are three ranks, in ascending order : Commandant, Lieutenant-colonel and Colonel (Capitaine de corvette, Capitaine de frégate and Capitaine de vaisseau in the naval forces), while brigadiers rank among officiers généraux.
In the German Bundeswehr, officers from Major, Oberstleutnant to Oberst in the Heer (Army) and Luftwaffe (Air Force), or from Korvettenkapitän, Fregattenkapitän to Kapitän zur See in the Deutsche Marine (German Navy) are traditionally known as Stabsoffiziere (English: Staff officers, in the meaning of field officers) OF-3, OF-4 and OF-5.
Field officer (Russian: ?-, Shtabofitser; derived from German: Stabsoffizier; translation en: Field officer), was the designation of a particular officers rank category (OF-3 to OF-5) of the Russian Imperial Army and Navy until 1917.
|Designation||Nevsky 1st infantry regiment||Ivanogorodsky 99th IR|
|rank category||Field Officers (?-?; Shtabofitsery)|
The British Army (in which these officers are called officers of field rank), and some others in the Commonwealth (including the Australian Army and New Zealand Army), also include the brigadier in this category: the equivalent in other armies is a general officer (the brigadier general).
The [U.S.] officer corps is divided into 10 Commissioned Officer pay grades (O-1 through O-10) and 5 Warrant Officer pay grades (WO1 through CW5):
- Officers in pay grades O-1 through O-3 are considered junior, or company grade, officers in the Army, Marine Corps, and Air Force, and are referred to as junior grade in the Navy. These pay grades correspond to the ranks of: second lieutenant (O-1), first lieutenant (O-2), captain (O-3) as well as Warrant Officer 1 (WO1) and Chief Warrant Officer 2 (CW2).
- Commissioned Officers in the next three pay grades (O-4 through O-6) are considered field grade officers in the Army, Marine Corps, and Air Force. These pay grades correspond to the ranks of: major (O-4), lieutenant colonel (O-5), colonel (O-6). The divisions of company grade and field grade have equivalent groupings in the Navy or Coast Guard, namely junior-grade officers and mid-grade officers.
- In the Navy or Coast Guard, officers in pay grades O-1 through O-4 are considered junior officers: ensign, lieutenant junior grade, lieutenant, lieutenant commander.
- In the Navy or Coast Guard, officers in the following pay grades (O-5 and O-6) are considered mid-grade officers: commander and captain.
The highest four pay grades are reserved for general officers in the Army, Marine Corps, and Air Force, and flag officers in the Navy and Coast Guard. The ranks associated with each pay grade are as follows: in the Army, Marine Corps, and Air Force, brigadier general (O-7), major general (O-8), lieutenant general (O-9), and general (O-10); in the Navy and Coast Guard, rear admiral-lower half, rear admiral-upper half, vice admiral, and admiral.