Provosts (usually pronounced "provo" in this context) are military police (MP) whose duties are policing solely within the armed forces of a country, as opposed to gendarmerie duties in the civilian population. However, many countries use their gendarmerie for provost duties.

As with all official terms, some countries have specific official terminology which differs from the exact linguistic meaning. The head of the military police is commonly referred to as the provost marshal, an ancient title originally given to an officer whose duty was to ensure that an army did no harm to the citizenry.

Military police are concerned with law enforcement (including criminal investigation) on military property and concerning military personnel, installation security, close personal protection of senior military officers, management of prisoners of war, management of military prisons, traffic control, route signing and resupply route management. Not all military police organizations are concerned with all of these areas, however. These personnel are generally not front-line combatants but, especially when directing military convoys, will be at or close to the front line. Some MPs, such as the U.S. Military Police Corps, are used as the primary defense force in rear area operations.

In many countries, military forces have separate prisons and judicial systems, different from civilian entities. The military possibly also has its own interpretation of criminal justice.