Otto (or Oddo) (c. 851 – 30 November 912), called the Illustrious (der Erlauchte) by later authors, is the Duke of Saxony from 880 to his death.

He is father of Henry the Fowler and grandfather of Otto the Great.

He is also father-in-law of Zwentibold, Carolingian King of Lotharingia.