William J. Bain (27 March 1896 – 22 January 1985) was a Canadian architect and a founder of the architecture firm, Naramore, Bain, Brady and Johanson, the predecessor to today's NBBJ. Bain was born in New Westminster, British Columbia. His family moved to Seattle while he was still young. Bain expressed an interest in architecture, and his father, a contractor, helped him get a job with Seattle architect , from whom he learned the rudiments of drafting and developed beginning skills in architecture. Bain served in France during World War I, and after the war enrolled in the architecture program at the University of Pennsylvania, from which he graduated in 1921.