Wilhelm Kettler was the Duke of Courland, a Baltic German region in today's Latvia. He ruled the western Courland portion of the Duchy of Courland and Semigallia, while his brother Friedrich ruled the eastern Semigallia portion.
- Occupation
- university teacher
- Born
- June 20, 1574
- Died
- April 7, 1640, April 17, 1640