the eighth enlisted rank in the U.S. Marine Corps, just above gunnery sergeant, below master gunnery sergeant, sergeant major, and Sergeant Major of the Marine Corps. It is equal in grade to first sergeant. It is abbreviated as "MSgt." In the U.S. Marine Corps, master sergeants provide technical leadership as occupational specialists at the E-8 level. General command leadership at this paygrade is provided by the separate rank of first sergeant.