Captain John Primrose Hay (4 April 1878 – 5 December 1949) was Labour MP for Glasgow Cathcart. Hay was born in Coatbridge and was educated at the Glasgow Free Church Training College, and the University of Glasgow. He became a lecturer in mathematics at Manchuria Christian College from 1906 to 1915, when he joined the Royal Garrison Artillery. He served in France for the remainder of World War I, becoming a captain.