William IX

William IX may refer to:

• William IX of Aquitaine (1071–1126)
• William IX, Count of Poitiers (1153–1156)
• William IX of Montferrat (1494–1518)
• Wilhelm, Duke of Jülich-Cleves-Berg (1516–1592)
• William I, Elector of Hesse (or Hesse-Cassel), also known as William IX, Landgrave of Hesse-Kassel, (1743–1821)

See also

• King William (disambiguation)
• Prince William (disambiguation)
• List of people named William#Royalty and nobility

1. William IX, Duke of Aquitaine
2. William IX, Count of Poitiers
3. William I, Elector of Hesse
4. Dangereuse de l'Isle Bouchard
5. William IX of Montpellier
6. Eleanor of Aquitaine
7. William IX, Marquis of Montferrat
8. Landgraviate of Hesse-Kassel
9. William X, Duke of Aquitaine
10. William, Duke of Jülich-Cleves-Berg
11. Troubadour
12. List of state leaders in the 12th century
13. Royal descendants of Queen Victoria and of King Christian IX
14. House of Plantagenet
15. Maria of Montpellier
16. William VIII, Duke of Aquitaine
17. Crusades
18. Louis IX of France
19. Henry II of England
20. Philippa, Countess of Toulouse