John N. McKay, PC, MP (born March 21, 1948) is a lawyer and a Liberal Canadian politician. As of 2006 he is the Member of Parliament for the riding of Scarborough—Guildwood.

John Harvey McKay (July 5, 1923 – June 10, 2001) was an American football coach. He was the head coach of the USC Trojans from 1960 to 1975, and of the Tampa Bay Buccaneers from 1976 to 1984.

John McKay (born 1939) is a mathematician at Concordia University in Canada, known for his discovery of monstrous moonshine, his joint construction of some sporadic simple groups, and for the Mc Kay correspondence relating certain finite groups to Lie groups.