A military tribune (Latin tribunus militum, "tribune of the soldiers", Greek chiliarchos, χιλίαρχος) was an officer of the Roman army who ranked below the legate and above the centurion. The tribunus militum should not be confused with the elected political office of Tribune of the Plebians (tribunus plebis) nor with that of the obsolete office of tribunus militum consulari potestate.
Military tribunes were appointed by the Committee of Tribes and the consuls for each legion, from the equestrian or senatorial classes. After the Marian reforms, the legion was organized tactically into six to ten cohorts, each commanded by a tribune. Some of the cohorts would be commanded by the military tribunes appointed by the Committee of Tribes, but the military tribunes often served administrative and political roles within the legion since service as a military tribune was the customary preparation for a political career. Any cohorts not commanded by a military tribune would be commanded by a tribunus cohortis, usually promoted from the centurions.