By-elections to the 33rd Canadian Parliament were held to fill vacancies in the House of Commons of Canada between the 1984 federal election and the 1988 federal election. The Progressive Conservative Party of Canada led a majority government for the entirety of the 33rd Canadian Parliament, though their number did decrease from by-elections.
Eleven seats became vacant during the life of the Parliament. Six of these vacancies were filled through by-elections, and five seats remained vacant when the 1988 federal election was called.
| By-election | Date | Incumbent | Party | Winner | Party | Cause | Retained | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lac-Saint-Jean | June 20, 1988 | Clément Côté | Progressive Conservative | Lucien Bouchard | Progressive Conservative | Resignation | Yes | |||||
| St. John's East | July 20, 1987 | James A. McGrath | Progressive Conservative | Jack Harris | New Democratic | Resignation | No | |||||
| Hamilton Mountain | July 20, 1987 | Ian Deans | New Democratic | Marion Dewar | New Democratic | Resignation | Yes | |||||
| Yukon | July 20, 1987 | Erik Nielsen | Progressive Conservative | Audrey McLaughlin | New Democratic | Resignation | No | |||||
| Pembina | September 29, 1986 | Peter Elzinga | Progressive Conservative | Walter van de Walle | Progressive Conservative | Resignation | Yes | |||||
| Saint-Maurice | September 29, 1986 | Jean Chrétien | Liberal | Gilles Grondin | Liberal | Resignation | Yes | |||||