William II of Holland, (February 1228-28 January 1256), was a count of Holland (1235-1256) and king of Germany (1247-1256). He was the son of Floris IV and Aleid van Gelre.

When his father was killed at a tournament at Corbie, William was only seven years old. His uncles William and Otto (bishop of Utrecht) were his guardians until 1239.

With the help of Henry II, Duke of Brabant and the archbishop of Cologne, he was elected in 1247 as king of Germany after Emperor Frederick II was excommunicated. After a siege of five months, he took Aachen in 1248 from Frederick's followers. Only then could he be crowned as king. Many of the German princes recognized his claim only after his marriage to Elizabeth of Brunswick in 1252.

In his home county, William fought with Flanders for control of Zeeland.In July 1253, he defeated the Flemish army at Westkapelle, and a year later a cease-fire followed.

From 1254, he fought a number of wars against the Frisians. In a battle near Hoogwoud on January 28, 1256, his horse fell through the ice, and in this vulnerable position, William was killed by the Frisians. His body was recovered 26 years later by his son Floris of Holland, who was only 2 years old when he succeeded his father. William was buried in Middelburg.

William gave city rights to Haarlem, Delft, 's-Gravenzande and Alkmaar. A castle he had built in 1248 was the beginning of the city of The Hague.

Preceded by: Conrad IV	King of Germany	Succeeded by: Alfonso of Castile
Preceded by: Floris IV	Count of Holland	Succeeded by: Floris V

de:Wilhelm von Holland fr:Guillaume II de Hollande nl:Willem II van Holland