Willem Krul (28 March 1722 – 4 February 1781), (also spelled as Krull or Crul) was a vice-admiral in the Dutch Navy in the latter 18th century, and then commander of the Dutch frigate Mars, during the American Revolutionary War. He was also known as Adrianus Hendrik Willem Krul. After serving in various assignments about the European Atlantic coast Krul served in his final naval assignment at Saint Eustatius, a Dutch possession in the West Indies, during which time he lost his life while engaged in a naval battle with the British, making him a national hero in the Netherlands.