William II (died 1226), Count of Perche and Bishop of Châlons, son of Rotrou IV, Count of Perche, and Matilda of Blois-Champagne, daughter of Theobald II, Count of Champagne, and Matilda of Carinthia, daughter of Engelbert, Duke of Carinthia.
He began his career as treasurer and provost of the Church of St. Martin of Tours, and was elected Bishop of Chalons in 1215, consecrated in 1216. The following year he succeeded his nephew Thomas, as Count of Perche, who was killed in the Battle of Lincoln.
He made a pilgrimage to Jerusalem in 1225, but died on the return trip. The House of Perche ended with his death, but several heirs attempted to revive the estate. Louis VIII the Lion argued the right of reversion and annexed the county of Perche to Peter, Count of Alençon. Peter assumed the title of Count of Perche, although this rank never achieved the status it had maintained during the previous dynasty.