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.

Prior to 1992, the Merchant Marine Atlantic War Zone Medal was a ribbon-only decoration; otherwise known as the Merchant Marine Atlantic War Zone Bar.

On May 19, 1992, the U.S. Department of Transportation announced the availability of new medals for civilian merchant seamen, in recognition of their service in World War II, Korea and Vietnam.

The medals are being issued to supplement war zone ribbon bars previously awarded to civilian mariners who supported the nation's armed forces in these wars.

[1] The new medal design consists of: The compass rose is traditionally associated with maritime navigation and the superimposed triangle with duty and service other than in the Armed Forces.