USS Gudgeon (SS-211) was the first American submarine to sink an enemy warship in World War II. She was the last of the long-range Tambor-class vessels commissioned for the United States Navy in the years before the country entered World War II. Gudgeon scored 14 confirmed kills, placing her 15th on the honor roll of American submarines. She was declared overdue, presumed lost with all hands, on 7 June 1944. Of the twelve Tambor-class submarines, only five survived the war.

The Tambor-class submarine was a United States Navy submarine design, used primarily during World War II. They were the USN's first fully successful fleet submarine, and began the war close to the fighting. Six of the class were in Hawaiian waters or the Central Pacific on 7 December 1941, with Tautog at Pearl Harbor during the attack. They went on to see hard service; seven of the twelve boats in the class were sunk before the survivors were withdrawn from front-line service in early 1945; this was the highest percentage lost of any US submarine class. Tautog was credited with sinking 26 ships, the largest number of ships sunk by a US submarine in World War II. The Tambors attained the top speed of 21 knots (39 km/h) and range of 11,000 nautical miles (20,000 km) of the preceding Sargo class, and improvements included six bow torpedo tubes, a more reliable full diesel-electric propulsion plant, and improved combat efficiency with key personnel and equipment relocated to the conning tower. In some references, the Tambors are called the "T Class", and SS-206 through SS-211 are sometimes called the "Gar class".