William Stewart Cornyn (1906–1971) was a Canadian-born American linguist and author, noted for his expertise in Burmese and Russian language studies, as well as for his research on Athabaskan and Burman etymology.

In 1922, he moved to Los Angeles where he first found work as a stock clerk, hall boy, and bookkeeper.

He lived in San Francisco from 1924 to 1928, working as an insurance clerk, eventually returning to Los Angeles.

He graduated from University of California, Los Angeles (BA with highest honors, 1940), and did graduate work at Yale (AM 1942, PhD 1944),[2] where he served as a professor of Slavic and South East Asian Linguistics and chair of both the Department of Slavic Languages and Literatures, and the Russian Area Program.

William Cornyn became a member of the Linguistic Society of America in 1941 while working as an Assistant in Germanic Languages at UCLA.