William II (c. 1348 – 25 June 1408) was born in Jülich, as the son of Gerhard VI of Jülich, Count of Berg and Ravensberg, and Margaret, daughter and heiress of Otto IV, Count of Ravensberg, and Margaret of Berg.
William fought the counties of Mark and Cleves to prevent them from combining but in 1397 he was taken prisoner in the battle of Kleverhamm.
He lost Remagen, Kaiserwerth and Sinzig to his nephew Adolf IV, Count of Kleve-Mark and due to these losses, his sons turned against him and imprisoned him in 1403/04.
He ultimately forced them to submit and later supported his brother-in-law Rupert, King of Germany against Guelders-Jülich and won the county of Blankenburg.
William died on 25 June 1408 and is buried in the Abteikirche in Altenberg.