Wilhelm Kettler
| Wilhelm Kettler | |
|---|---|
| Duke of Courland and Semigallia | |
 | |
| Reign | 1587–1617 |
| Predecessor | Gotthard Kettler |
| Successor | Friedrich Kettler |
| Born |
20 June 1574 Mitau, Duchy of Courland and Semigallia |
| Died |
20 April 1640 (aged 65) Kucklow, Duchy of Pomerania |
| Burial | Ducal crypt in the Jelgava Palace |
| Spouse | Sophia of Brandenburg-Prussia |
| Issue | Jacob Kettler |
| House | House of Kettler |
| Father | Gotthard Kettler |
| Mother | Anna of Mecklenburg |
| Religion | Lutheranism |
Wilhelm Kettler (20 June 1574 in Mitau – 7 April 1640 in Kucklow) was the second Duke of Courland, a region of Latvia. Wilhelm ruled the western Courland portion of the Duchy of Courland and Semigallia while his brother Friedrich ruled the eastern Semigallia portion.
Wilhelm Kettler was the youngest son of Gotthard Kettler and his wife Anna of Mecklenburg. After their father's death in 1587, Wilhelm and his brother Friedrich inherited the Duchy of Courland. The brothers decided to divide the duchy between themselves. Wilhelm ruled the Courland portion with the seat in Kuldīga. In 1609 he married Princess Sophia of Brandenburg-Prussia (1582–1610), daughter of Albert Frederick, Duke of Prussia, receiving as a dowry the territory of Grobiņa. Due to conflicts with the nobility, he lost the duchy in 1617 and emigrated.
He died in the Kucklow abbey in Pomerania on 7 April 1640. His son, Duke Jacob Kettler of Courland, had his remains returned to Courland in 1642. He was interred in the duchy tomb on 23 February 1643.