John Kay was a clockmaker from Warrington, Lancashire, England. He is known by association with Richard Arkwright for the invention of the spinning frame in 1767: an important stage in the development of textile manufacturing in the Industrial Revolution.
Kay was originally a partner of Thomas Highs (who seems to have been the true inventor) but they ran out of funds. Arkwright took Kay and the idea of the spinning frame and exploited both, with Kay doing the construction and development work that led to the creation of the water frame which made Arkwright's fortune and reputation (almost to the exclusion of Kay and Highs).
This John Kay should not be confused with the man from Bury who invented the flying shuttle. The two men worked separately and were not related.