William Arthur Irwin, OC, often credited as W. Arthur Irwin (May 27, 1898 – August 9, 1999), was a Canadian journalist and diplomat. He is best known for his work on Maclean's, a magazine with which he held various positions across a quarter of a century. He also served as the Commissioner of the National Film Board of Canada (NFB), and as Canadian high commissioner or ambassador to various countries.