Activated during the Vietnam War, the Brigade oversaw all Military Police operations in the country for a large portion of the conflict, undertaking a wide variety of missions throughout the country and providing command and control for other military police groups in the region.

The 18th Military Police Brigade is assigned to the 21st Theater Sustainment Command of United States Army Europe.

[4] On 26 September 1966, the Brigade assumed operational control over all non-divisional military police units in South Vietnam.

The units were stationed throughout every corps tactical zone, ranging from Da Nang in the north to Soc Trang in the south.

[4] Members of the Brigade performed a wide variety of missions including evacuation of prisoners of war, security of vessels and ports, convoy escort, security of vital installations and VIPs, maintenance of discipline, law and order and direct support to combat operations.

The Brigade's MPs conducted over 24,000 combat patrols, apprehended over 2,400 criminals, confiscated 7,500 illegal weapons, and trained over 10,000 Iraqi police officers.

[3] The 127th and 630th Military Police Companies began serving in Iraq in support of Operation Iraqi Freedom II in mid-2007.

[9] The transition ceremony for this command was held on 30 October as 100 soldiers from the brigade's headquarters took charge of the 89th's area of responsibility.

[11] The brigade is supporting Iraqi police logistics, personnel management, maintenance, budget, operations, training, leadership and judicial integration.

[citation needed] The brigade cased its colors on 2 December 2008 and began redeploying back to its home bases.