William II, Count of Holland was a nobleman who ruled from 1256 until his death in 1257. He was a member of the House of Avesnes and succeeded his father, William I, as count. His reign was marked by efforts to strengthen the power of the countship and manage conflicts with neighboring regions. William II's rule was short-lived, as he died young, possibly due to illness. After his death, the countship passed to his half-brother, Florence, who continued the family's influence in the region. William II's legacy is often overshadowed by the more prominent figures in the Holland nobility.