Nicholas I Sanudo (or Niccolò; died 1341) was the fifth Duke of the Archipelago from 1323 to his death. He was the son and successor of William I of the House of Sanudo. Nicholas fought under his brother-in-law Walter, Duke of Athens, at the disastrous Battle of Halmyros on 15 March 1311. He was one of the few knights on the losing side to escape with his life and liberty. He was succeeded by his brother John I. His other brother was Marco Sanudo, Lord of Milos.