Conservative MP Scott Aitchison to resign seat by end of year
The former leadership contender and housing critic informed Pierre Poilievre of his decision last week.
Explainer
Conservative MP and former leadership contender Scott Aitchison is expected to resign his seat in the House of Commons by the end of the year.
Three sources told CBC News that Aitchison, the MP for Ontario's Parry Sound-Muskoka, is expected to resign later this fall.
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A senior Conservative source said Conservative Leader Pierre Poilievre was told last week that Aitchison plans to leave at the end of the fall sitting.
Two sources with knowledge of the discussion told The Globe and Mail that Aitchison informed Poilievre last week of his decision to resign.
Why is Scott Aitchison resigning?
The two sources both characterized Aitchison’s decision to leave as a desire to try something else beyond elected life.
One of the sources said Aitchison was ready to move on after spending more than 30 years in elected politics.
He has been in politics since 1994, first serving as a city councillor in Huntsville, Ont., before becoming mayor from 2014 to 2019 and then an MP.
A source close to Aitchison confirmed to the National Post that the MP is planning to resign his seat before the end of 2026 to pursue “other opportunities.”
Aitchison is expected to release a statement addressing his resignation on Wednesday, according to sources who spoke to the Toronto Star.
His office did not immediately return requests for comment from CBC News and The Globe and Mail.
What does this mean for the Conservative Party?
Aitchison's resignation would add him to a list of Conservative MPs exiting electoral politics in recent months.
It marks the eighth departure for Poilievre since the 2025 election and the eighth party member to leave the caucus since the last election.
Former MPs Larry Brock and Cathay Wagantall both stepped down in the past month. Brock officially resigned his seat earlier this month.
Four Conservative MPs have crossed the floor to the Liberals since last November.
Another, Quebec MP Richard Martel, resigned his seat for a Senate appointment. The Conservatives subsequently lost his riding in the August by-election.
Aitchison's exit raises the number of outstanding byelections Prime Minister Mark Carney must call to seven.
Polling aggregator 338Canada suggests that Parry Sound, Muskoka could flip to the Liberals if a byelection were held today.
Aitchison won the riding in 2025 with a 10 point lead over the Liberals.
The site currently lists both Brantford, Brant South and Parry Sound, Muskoka as “leaning Liberal.”
Poilievre will also eventually have to fight to maintain the Ontario riding of Brantford, Brant South left vacant after Brock's resignation.
Who is Scott Aitchison?
Aitchison has been the MP for Parry Sound-Muskoka since the 2019 election.
He won the riding in the 2025 election with 52.2 per cent of the vote.
The former Huntsville mayor launched a bid in the 2022 Conservative leadership campaign that saw Poilievre chosen as the party's leader.
Aitchison finished fifth. He also ran for Conservative leadership against Pierre Poilievre in 2022, where he finished fourth in a pool of four candidates.
Housing was a key feature of his leadership campaign, and Poilievre later named him the party's housing critic.
The Conservatives have held Parry Sound, Muskoka since 2006. The riding was previously represented by former Harper cabinet minister Tony Clement.
What is the current state of the House of Commons?
The resignation would create another vacancy in the House, where six seats are currently empty.
The Conservatives currently hold 137 seats, including Aitchison's.
Prime Minister Mark Carney has a majority government with 173 seats.
The most recent polling data from Nanos Research suggests support for the Liberals stands at 49.9 per cent, with the Conservatives at 27.9 percent.
In addition to the Conservative vacancies, former Liberal cabinet minister Steven Guilbeault officially resigned last month, and former Liberal MP Shaun Chen resigned in mid-August.
Former NDP MP Alexandre Boulerice and the Bloc Québécois's Simon-Pierre Savard-Tremblay both left federal politics to run in Quebec's provincial election.
By-elections have not been called yet to fill the existing vacancies.
In anticipation of an upcoming byelection in Brantford, Brant South, Poilievre appointed Brantford Mayor Ken Davis as the party's candidate, forgoing a nomination contest.
That decision was met with disappointment from local pastor Dave Carol, who had been endorsed by both Brock and his predecessor.
With files from CBC News, National Post and The Globe and Mail