William VI
William VI may refer to:
- William VI, Duke of Aquitaine
- William VI, Count of Auvergne
- William VI of Montpellier
- William VI, Marquess of Montferrat
- William II, Duke of Bavaria, also William VI of Holland
- William the Younger, Duke of Brunswick-Lüneburg
- William VI, Landgrave of Hesse-Kassel
- William I of the Netherlands, also William VI of Orange