The 2025 Terrebonne provincial by-election was held on March 17, 2025. It was triggered after the resignation of Pierre Fitzgibbon from the National Assembly of Quebec.
The main settlement in the seat is the city of Terrebonne, a suburb on the North Shore of Montreal.
Once a stronghold of the Parti Québécois (PQ), Terrebonne was first won by Pierre Fitzgibbon for the Coalition Avenir Québec (CAQ) in the 2018 Quebec general election.
The by-election is considered a test of leadership for Premier François Legault. A major issue is the United States trade war with Canada and Mexico.
Advance voting was open from March 9 to March 10.
There are nine candidates:
Nadia Poirier, a second-time QS nominee, complained afterwards about the lack of support she received from the party, noting that none of its 12 MNAs came out to help in her campaign and that the party had solidarity in name only. The party responded that, as Terrebonne had been a péquiste stronghold for 25 years, it allocated its resources based on a serious analysis of its chances of winning. In June 2025, Poirier announced that she was leaving QS to join the PQ.