Kay is an English surname.
It derives from the Old Breton and Welsh cai and the Cornish key meaning "wharf", or from the Old English coeg meaning "key".
[1][2] The surname is also a diminutive of MacKay and McKay.
[3][4] In England, the Kay(e)s of Lancashire and Yorkshire are believed to be related to the ancient Kaye family of Woodesham, Yorkshire, and there is also a Kay Family Association.
[5] Notable people with this surname include: