Wenceslaus I may refer to:

  • Saint Wenceslaus I, Duke of Bohemia (907–935 or 929), and subject of a Christmas carol
  • Wenceslaus I of Bohemia (c. 1205–1253), King of Bohemia
  • Wenceslaus I of Legnica (c. 1318 – 1364)
  • Wenceslaus I, Duke of Luxembourg (1337–1383), the first Duke
  • Wenceslaus I, Duke of Saxe-Wittenberg (1337—1388)
  • Wenceslaus I, Duke of Opava (1361–1381)
  • Wenceslaus I, Duke of Cieszyn (1413/18 – 1474)
  • Wenceslaus I of Zator (c. 1418 – before 29 July 1468)