Military police

The Security icon has the letters "MP" on it.

Military Police, more popularly referred 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 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.