William of Orange is the name of several historical people. They are also sometimes known under the Dutch version of the name, Willem.

There are five Stadtholders in the Dutch Republic and three kings in the subsequent Kingdom of the Netherlands.

• William I of Orange is more commonly known as William the Silent.
• William II of Orange.
• William III of Orange is better known as King William III of England, because he became king of England in 1688.

The House of Orange died out in the direct line, but a sideline (the Stadtholders of Friesland), inherited the title.

• William IV of Orange.
• William V of Orange had to flee the Netherlands in 1795.

After the French Revolution the son of Willem V returned to the Netherlands and became:

• King William I of the Netherlands.
• His son was King William II of the Netherlands.
• And grandson King William III of the Netherlands.

Usually, the name William of Orange means William I of Orange when discussing Dutch, William III of Orange when discussing English history.