The United States Air Force Security Forces (SF) are the ground combat force and military police service of the U.S. Air Force and U.S. Space Force. The USAF Security Forces were formerly known as Military Police (MP), Air Police (AP), and Security Police (SP) at various points in their history. Due to its significant ground combat mission, Security Forces are sometimes regarded as Air Force infantry within the Air Force and were formed on the premise of being the Air Force's "Marine Corps", in that they would provide security for the Air Force similar to how the Marines provide security for the Navy.

Military police (MP) are law enforcement agencies connected with, or part of, the military of a state. In wartime operations, the military police may support the main fighting force with force protection, convoy security, screening, rear reconnaissance, logistic traffic management, counterinsurgency, and detainee handling.