# By-elections to the 13th Canadian Parliament

By-elections to the 13th Canadian Parliament were held to elect members of the House of Commons of Canada between the 1917 federal election and the 1921 federal election. Prime Minister Robert Borden, then Arthur Meighen, led a majority government consisting members collectively known as the Unionist Party, during the 13th Canadian Parliament.
The list includes Ministerial by-elections which occurred due to the requirement that Members of Parliament recontest their seats upon being appointed to Cabinet. These by-elections were almost always uncontested. This requirement was abolished in 1931.
| By-election | Date | Incumbent | Party | Winner | Party | Cause | Retained |
| Medicine Hat | June 27, 1921 | Arthur Lewis Sifton | Unionist | Robert Gardiner | Progressive | Death | No |
| Yamaska | May 28, 1921 | Oscar Gladu | Laurier Liberal | Aimé Boucher | Liberal | Death | Yes |
| York—Sunbury | May 28, 1921 | Harry Fulton McLeod | Unionist | Richard Hanson | Conservative | Death | Yes |
| Peterborough West | February 7, 1921 | John Hampden Burnham | Unionist | George Newcombe Gordon | Liberal | Resignation | No |
| Yale | November 22, 1920 | Martin Burrell | Unionist | John Armstrong MacKelvie | Conservative | Appointed Librarian of Parliament | Yes |
| Elgin East | November 22, 1920 | David Marshall | Unionist | Sydney Smith McDermand | United Farmers | Death | No |
| St. John—Albert | September 20, 1920 | Rupert Wilson Wigmore | Unionist | Rupert Wilson Wigmore | Conservative | Recontested upon appointment as Minister of Customs and Inland Revenue | Yes |
| Colchester | September 20, 1920 | Fleming Blanchard McCurdy | Unionist | Fleming Blanchard McCurdy | Nationalist Liberal | Recontested upon appointment as Minister of Public Works | Yes |
| Timiskaming | April 7, 1920 | Francis Cochrane | Unionist | Angus McDonald | Independent | Death | No |
| St. James | April 7, 1920 | Louis Audet Lapointe | Laurier Liberal | Fernand Rinfret | Liberal | Death | Yes |
| Kamouraska | March 31, 1920 | Ernest Lapointe | Laurier Liberal | Charles Adolphe Stein | Liberal | Resignation to contest Quebec East by-election | Yes |
| Ontario North | December 9, 1919 | Samuel Simpson Sharpe | Conservative | Robert Henry Halbert | Independent | Death | No |
| Quebec East | October 27, 1919 | Wilfrid Laurier | Laurier Liberal | Ernest Lapointe | Laurier Liberal | Death | Yes |
| Glengarry and Stormont | October 27, 1919 | John McMartin | Unionist | John Wilfred Kennedy | United Farmers | Death | No |
| Assiniboia | October 27, 1919 | John Gillanders Turriff | Unionist | Oliver Robert Gould | United Farmers | Called to the Senate | No |
| Victoria City | October 27, 1919 | Simon Fraser Tolmie | Unionist | Simon Fraser Tolmie | Unionist | Recontested upon appointment as Minister of Agriculture. | Yes |
| Prince | October 20, 1919 | Joseph Read | Liberal | William Lyon Mackenzie King | Liberal | Death | Yes |
| Kingston | October 20, 1919 | William Folger Nickle | Conservative | Henry Lumley Drayton | Unionist | Resignation | Yes |
| Victoria—Carleton | October 17, 1919 | Frank Carvell | Unionist | Thomas Wakem Caldwell | United Farmers | Appointed Chairman of the Board of Railway Commissioners | No |
| Lanark | May 2, 1918 | Adelbert Edward Hanna | Unionist | John Alexander Stewart | Unionist | Death | Yes |