The Marine Corps Expeditionary Medal is a military award of the United States Marine Corps. It was established on 8 May 1919 as the Marine Corps Expeditionary Ribbon. A full-sized medal was authorized on 1 March 1921. The Marine Corps Expeditionary Medal is therefore one of the oldest medals of the United States military which is still issued to active duty personnel.

A service star is a miniature bronze or silver five-pointed star 3⁄16 inch (4.8 mm) in diameter that is authorized to be worn by members of the eight uniformed services of the United States on medals and ribbons to denote an additional award or service period. The service star may also be referred to as a campaign star or battle star depending on which award the star is authorized for and the manner in which the device is used for the award. "Battle star" is also the term used to refer to decorations issued by the United States Navy during World War II and the Korean War to individual ships, recognizing a vessel's participation in a particular battle or operation.