Military police

Military Police, more popularly refered to and thought of as MPs, are concerned with law enforcement 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. However, not all military police organizations are concerned with all of these. MP's are generally not frontline combat personnel, but their duties may bring them near the frontline.

The head of the military police is commonly referred to as the Provost Marshal. This ancient title was originally given to an officer whose duty it was to ensure that the army of the king did no harm to the citizenry.

The UNSC Marine Corps maintains its own military police, used to guard military installations on Reach and Earth, as well as other high priority installations. It is unknown whether the UNSC Army maintains its own MP's, though it is presumed that Marine MP's also function with in coordination with the UNSC Navy. ODST MP's formed a security detail for the Master Chiefs testing of the Mark V MJOLNIR Armor.