Sir William Twysden, 1st Baronet (1566–1628) was an English politician who sat in the House of Commons at various times between 1593 and 1628.
Twysden was the son of Roger Twysden, of Roydon Hall, East Peckham, and his wife Anne Wyatt, daughter of Sir Thomas Wyatt of Allington Castle, Kent. He was admitted to Gray's Inn on 28 October 1584 and succeeded his father in the estate at East Peckham in November 1603. He was appointed a Gentleman Usher of the Privy Chamber to James I and knighted at Charterhouse on 11 May 1603.
In 1593, he was elected Member of Parliament for Clitheroe, in 1601 MP for Helston and in 1606 MP for Thetford. He was created a baronet on 29 June 1611. In 1614, he was re-elected MP for Thetford and finally served as MP for Winchelsea from 1628 until his death.
Twysden was a great collector of manuscripts and knew Hebrew, Greek, and other languages.
He died in his 63rd year and was buried at East Peckham with a monumental inscription. He had married Anne Finche, daughter of Sir Moyle Finch, 1st Baronet. His son Roger succeeded him in the baronetcy.