Sergeant (/ˈsɑː(r)dʒənt/ SARJ-ənt;^[1] abbreviated to Sgt. and capitalized when used as a named person's title) is a rank in many uniformed organizations, principally military and policing forces. The alternative spelling, serjeant, is used in The Rifles and other units that draw their heritage from the British Light Infantry. Its origin is the Latin serviens, 'one who serves', through the French term sergent.

The term sergeant refers to a non-commissioned officer placed above the rank of a corporal and a police officer immediately below a lieutenant or, in the UK Police forces, below an inspector.^[2][3] In most armies the rank of sergeant corresponds to command of a squad (or section). In Commonwealth armies, it is a more senior rank, corresponding roughly to a platoon second-in-command. In the United States Army, sergeant is a more junior rank corresponding to a four-soldier fireteam leader.

More senior non-commissioned ranks are often variations on sergeant, for example staff sergeant, first sergeant, and sergeant major.

Many countries use sergeant rank, whether in English or using a cognate with the same origin in another language. The equivalent rank in Arab armies is raqīb (رقيب‎), meaning 'overseer' or 'watcher'.