William of Orange (French: Guillaume, Dutch: Willem) is the name of several historical people. In the context of English history, it refers most often to William III of England; in the context of Dutch history, William the Silent is most often meant.

These men could be meant by William of Orange:

• Saint William of Gellone (755-c.812), legendary courtier of Charlemagne who defeated the Saracens at Orange, is often called William of Orange.
• William of Orange was also a bishop accompanying the First Crusade. After the death of Adhemar of Le Puy, he was recognized as leader of the clergy, until he himself died six months later in December of 1098.

The following princes of Orange were also known as William of Orange:

• William I of Baux (c.1155-1218)
• William II of Baux (c.1200-1239)
• William III of Baux (c.1220-1256)
• William IV of Baux (c.1240-1281)
• William VIII of Chalon (c.1415-1475)

After the counts of Nassau inherited the principality, the following princes of Orange-Nassau (and stadtholders in the Netherlands) were also known as William of Orange:

• William I of Orange-Nassau, (1533-1584), also known as William the Silent
• William II of Orange-Nassau
• William III of Orange-Nassau, also king of England
• William IV of Orange-Nassau
• William V of Orange-Nassau

The following kings of the Netherlands from the House of Orange-Nassau may also sometimes be known as William of Orange:

• William I of the Netherlands.
• William II of the Netherlands
• William III of the Netherlands.