John Keigwin (1641–1716) was a Cornish antiquary, born at Mousehole, Cornwall. He was a leading member of a group of antiquaries in west Penwith: this group also included John and Thomas Boson, William Gwavas, Thomas Tonkin, William Borlase, Oliver Pender, and James Jenkins of Alverton. His teacher was John Boson. In addition to Cornish and English, Keigwin had a command of the French, Latin, Greek and Hebrew languages.