| William Erskine Knowles | |
| Constituency Mp1: | Assiniboia West |
| Parliament1: | Canada |
| Predecessor1: | Thomas Walter Scott |
| Term Start1: | 1906 |
| Term End1: | 1908 |
| Constituency Mp2: | Moose Jaw |
| Parliament2: | Canada |
| Successor2: | James Alexander Calder |
| Term Start2: | 1908 |
| Term End2: | 1917 |
| Office3: | Member of the Legislative Assembly of Saskatchewan for Moose Jaw City |
| Term Start3: | 1918 |
| Term End3: | 1921 |
| Term Start4: | 1925 |
| Term End4: | 1927 |
| Birth Date: | 28 November 1872 |
| Birth Place: | Alliston, Ontario, Canada |
| Nationality: | Canadian |
| Party: | Liberal |
| Otherparty: | Saskatchewan Liberal Party |
| Cabinet: | Minister of Telephones (1919-1921) Provincial Secretary (1918-1921) |
William Erskine Knowles (November 28, 1872 - July 17, 1951) was a Canadian politician.
Born in Alliston, Ontario, Knowles was educated at Osgoode Hall Law School in Toronto, Ontario. A lawyer by profession, he was first elected to the House of Commons of Canada for the electoral district of Assiniboia West in a by-election held on February 6, 1906. A Liberal, he was re-elected in 1908 and 1911 for the electoral district of Moose Jaw. He did not run in 1917. From 1918 to 1927, he was a member of the Legislative Assembly of Saskatchewan. From 1918 to 1921, he was the Provincial Secretary and from 1919 to 1921 he was the Minister of Telephones. He attempted a federal comeback in the 1921 and 1923 elections but was defeated.
Knowles resigned his seat in the Saskatchewan assembly in 1927 after he was named a judge.[1]
By-election: On Mr. Scott's resignation to enter provincial politics in Saskatchewan, 29 August 1905.