Joanna de Haydock (née de Dutton; 1335 – ????) was the 22nd great-grandmother of Cometan, classified as one of Cometan’s medieval paternal ancestors in the Taylor family line. Born in Runcorn, Cheshire, Joanna was the wife of John de Haydock and is also known to have been the daughter of Sir Thomas Dutton and Baroness Eleanor Dutton. The details surrounding Joanna’s death remain unknown.
In Cometanic ancestry, Joanna de Haydock is categorised as part of the 24th generation retrograde, and because she was born before 1453, she is classified as a medieval ancestor of Cometan, a title that is rarely bestowed.