Allan Stuart Hay FRS (born July 23, 1929 in Edmonton, Alberta) is a Canadian chemist, and Tomlinson Emeritus Professor of Chemistry at McGill University. He is best known for his synthesization of Polyphenylene Oxide, leading to the development of Noryl and various other plastics.
He graduated from University of Alberta with a B.Sc. in 1950, and University of Illinois with a Ph.D. in 1955. He was a research chemist, and manager at General Electric, from 1955 to 1988. In 1975, he was adjunct faculty, at University of Massachusetts Amherst. In 1981, he was named a fellow of the Royal Society of London. In 1984 he received the IRI Achievement Award from the Industrial Research Institute in recognition for his contributions to science and technology, and society generally, for discoveries in polymerization by oxidative coupling.