Otto, Duke of Brunswick and Lunenburg (Grubenhagen) (1320 1 December 1398) was the fourth and last husband of Joan I of Naples. He also held the title of Prince of Taranto nicknamed as Otto the Tarantine. He was the eldest son of Henry II (c. 1289 - 1351) and his first wife Jutta of Brandenburg. In 1353, he married his first wife Violante of Vilaragut, a daughter of Berengar de Villaragut and widow of James III of Majorca. There were no children from this marriage. By 1372, Otto was a widower. On 25 September 1376, Otto married his second wife Queen regnant Joan I of Naples. The groom was fifty-six years old and the bride about forty-eight. He became King consort but again there were no children.