William (929 – 2 March 968) was Archbishop of Mainz from 17 December 954 until his death.
He was the son of the Emperor Otto I the Great and a Wendish mother.
[1] On 17 December 954, he was appointed to the archbishopric of Mainz following the death of the rebellious former archbishop Frederick.
From his father, William also received the title of "Arch-Chaplain of the Empire."
William died at Rottleberode in 968 and was buried in St. Alban's Abbey, Mainz.