Otto IV may refer to:

• Otto IV, Count of Wittelsbach (c. 1083 – 1156)
• Otto IV, Holy Roman Emperor (1175–1218)
• Otto IV, Count of Ravensberg (c.  1276–1328)
• Otto IV, Count of Burgundy (1248–1302)
• Otto IV, Margrave of Brandenburg-Stendal (c. 1238 – 1308 or 1309)
• Otto IV, the Merry (1301–1339), Duke of Austria
• Otto IV, Duke of Lower Bavaria (1307–1334)
• Otto IV, Prince of Anhalt-Bernburg (d. 1415)
• Otto IV, Duke of Brunswick-Lüneburg or Otto the Lame (d. 1446), Prince of Lüneburg
• Otto IV, Count of Waldeck (c. 1440–1494), of Landau
• Otto IV, Count of Rietberg (d. 1553)
• Otto IV of Schaumburg (1517–1576)