The Dewey Medal was a military decoration of the United States Navy which was established by the United States Congress on June 3, 1898. The medal recognizes the leadership of Admiral of the Navy George Dewey, during the Spanish-American War, and the sailors and marines under his command.

The Dewey Medal was created to recognize the forces of the U.S. Navy and United States Marine Corps who participated in the Battle of Manila Bay. To be awarded the Dewey Medal, a service member must have served in one of the following naval vessels on May 1, 1898:

• U.S.S. Baltimore
• U.S.S. Boston
• U.S.S. Concord
• U.S.S. McCulloch
• U.S.S. Nanshan
• U.S.S. Olympia
• U.S.S. Petrel
• U.S.S. Raleigh
• U.S.S. Zafiro

The Dewey Medal was a one-time only decoration and there were no devices or campaign stars authorized to the medal. The medal consists of a circular medallion, upon which rests an image of Admiral George Dewey, suspended from a blue and yellow ribbon. Admiral Dewey himself was awarded the medal, although he always wore it with the medal's reverse displayed which depicted a Navy gun crew.

The medal was recognized as being given for active military duty; yet because it recognized a single battle in a single campaign, the Dewey Medal quickly became regarded as a commemorative medal and did not appear on U.S. Navy and Marine Corps precedence charts. When worn on a military uniform, however, the Dewey Medal was considered equal to the Spanish Campaign Medal and senior to the Sampson Medal.