Sir William Walworth (died 1385) was an English nobleman and politician who was twice Lord Mayor of London (1374–75 and 1380–81).

He was apprenticed to John Lovekyn, who was a member of the Fishmongers Guild, whom he succeeded as Alderman of Bridge ward in 1368.

John Gardner, in The Life and Times of Chaucer, contends that Walworth were one of a number of important merchants, all friends of Alice Perrers, who manipulated Edward III.

[3] Walworth's most famous exploit was his encounter with Wat Tyler during the English peasants' revolt of 1381, in his second term of office as Lord Mayor.

[4] Walworth raised the city bodyguard in the king's defence, for which service he was rewarded by knighthood and a pension.