Sometime before November 16, 2021, a by-election will be announced for the seat in the House of Commons representing Haldimand–Norfolk in the province of Ontario.

On May 20, the Chief Electoral Officer of Canada, Stéphane Perrault, received official notice from the Speaker of the House of Commons that the seat for Haldimand–Norfolk (Ontario) became vacant following the resignation of Diane Finley. On May 11, Finley resigned from her seat in the House of Commons, explaining she was leaving on the same date of the death of her late husband, Senator Doug Finley. “It just seems fitting and symbolic that I also end my service and exit politics on the same date,” explained MP Finley in her press release.

Under the law, the by-election date must be announced between May 31 and November 16, 2021, and will signal the start of the by-election period. According to Elections Canada, the earliest date the by-election can be held is July 12, 2021.