Ernst Kals (2 August 1905 – 2 November 1979) was a Kapitän zur See with the Kriegsmarine during World War II. He commanded the Type IXC U-boat on five patrols, and sank twenty ships, for a total of 145,656 tons of Allied shipping, becoming the sixteenth highest scoring U-Boat ace of World War II. He was awarded the Knight's Cross of the Iron Cross, awarded to recognise extreme battlefield bravery or successful military leadership.