William Turnbull (died 3 September 1454) was a Scottish politician and bishop, credited with founding Jedburgh Grammar School and the University of Glasgow.
He came from Bedrule in the Scottish Borders, where a plaque in the local church is erected in his memory.
Upon his return to Scotland, he befriended King James II and became Keeper of the Privy Seal (1440–1448) and Royal Secretary (1441–1442).
During his time as Bishop, he pursued the formation of a university in Glasgow with the encouragement of King James.
On 7 January 1451, Pope Nicholas V issued a papal bull decreeing the foundation of the University of Glasgow, which started classes in the Glasgow Cathedral buildings, with Turnbull as the first chancellor.