John of Denmark or Hans of Denmark may refer to:

• John of Dacia, author of Summa Grammatica (c. 1280)
• John, King of Denmark (r. 1455–1513)
• John of Denmark (1518–1532), heir apparent to Christian II of Denmark
• John II, Duke of Schleswig-Holstein-Haderslev (1521–1580)
• John II, Duke of Schleswig-Holstein-Sonderburg (1545–1622)
• John, Prince of Schleswig-Holstein (1583–1602)
• Prince Johann of Schleswig-Holstein-Sonderburg-Glücksburg (1825–1911)