Werner Friedrich Adolf Hartmann (11 December 1902 – 26 April 1963) was a German U-boat commander in World War II. He sank 26 ships, amounting to over 115,000 gross register tons (GRT) sunk, making him the 25th most successful U-boat commander of the war. He was also a recipient of the Knight's Cross of the Iron Cross with Oak Leaves (German: Ritterkreuz des Eisernen Kreuzes mit Eichenlaub).