Ross and Macdonald was one of Canada's most notable architecture firms in the early 20th century. Based in Montreal, Quebec, the firm originally operated as a partnership between George Allen Ross and David MacFarlane ("Ross and MacFarlane") from 1907 to 1912. MacFarlane retired in 1913, and Robert Henry Macdonald became a partner. The Ross and Macdonald name was used until 1944.