The Merchant Marine Atlantic War Zone Medal (Bar) is a decoration of the United States Merchant Marine established by an Act of Congress on May 10, 1944.
The decoration is awarded to officers and men of ships operated by the War Shipping Administration for service in the Atlantic War Zone between December 7, 1941, and November 8, 1945. This theatre of operations comprised the North Atlantic Ocean, South Atlantic Ocean, Gulf of Mexico, Caribbean Sea, Barents Sea, and Greenland Sea.