Election '25 Deep Dive: Where the Liberals lost their majority in Ontario
Ontario was a two-party race as the NDP vote collapsed.
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It’s usually the case that Ontario is the key battleground in every election, but in the 2025 campaign the province proved to be the decisive battleground that denied Mark Carney’s Liberals a majority government.
This is the first in a three-part series of deep dives into the 2025 federal election results. After analyzing and obsessing for months in the run-up to the election, it seems a shame to move on from the results too quickly — particularly as they will provide the baseline for the next few years’ worth of analysis ahead of the next election.
So, let’s dive in, starting with Ontario. The second instalment will look at Atlantic Canada and Quebec and the third will focus on Western Canada.
With 49.2% of the vote, a gain of 10 points from the 2021 election, the Liberals captured their highest share of the vote in the province since Jean Chrétien took 51.5% in the 2000 campaign. Despite the strong performance, the Liberals nevertheless won only 70 seats, eight fewer than they did in the last election.
The Conservatives made a gain of 15 seats and nine percentage points, winning 43.8% of the vote. While impressive, that is just below the 44.4% vote share captured by Stephen Harper in his 2011 majority victory.
As these two parties rose up, all other parties fell back — especially the New Democrats. The NDP was shutout of the province and took just 4.8% of the vote, a slide of 13 points from the last election. That is the worst performance for the party in its entire history. You have to go back to 1940 to find a worse result for its CCF predecessor.
The Greens and People’s Party also dropped, with the Greens’ vote share being cut in half to 1.1% and the PPC sliding nearly five points to just 0.7%.
While voters can go every which way, one common thread we’ll see in the sub-regional breakdowns below (with only a few exceptions) is that the Liberals’ growth was primarily driven by the slide of the NDP, while the Conservatives’ growth was a combination of the NDP’s decline and that of the People’s Party.
Positive vibes for the Liberals in Eastern Ontario
We’ll start our sub-regional tour of the province in Ottawa, one of the regions that bucked the broader Ontario trend the most.
The Liberals won Ottawa with an astonishing 62.4% of the vote, a gain of 17 points from the last election. The Conservatives dropped about one point to just 29.5%. The net swing of roughly 18 points to the Liberals was the biggest in Ontario, with the Liberals making gains of between 15 and 19 points in each riding in the city. The Conservatives largely held their own, except in Pierre Poilievre’s riding of Carleton.
There was certainly a local dynamic at play in this riding, as the Conservatives fell 6.2 points. That was the party’s biggest drop in all of Ontario and the fifth-biggest in Canada, and it was enough to flip Carleton to the Liberals and complete the party’s sweep of the national capital.
Generally, Eastern Ontario was rough for the Conservatives. The party lost vote share in only 16 ridings outside of Quebec and seven of them were in Eastern Ontario.
The NDP fell back to just 6.1% in Ottawa, a drop of 13 points that put them out of contention throughout the city, including in Ottawa Centre where there was a net 30.6-point swing between the Liberals and the NDP.
Outside of Ottawa, the Liberals did remarkably well in a region that is traditionally very friendly to the Conservatives. The Conservatives won Eastern Ontario outside of Ottawa by a margin of 11 points in 2021, but the Liberals’ 15-point gain in the region pushed them into a tie with the Conservatives at 47.4% apiece. This was enough to flip Bay of Quinte from the Conservatives to the Liberals, while the party’s 22.5-point gain in Kingston and the Islands was the second biggest for the Liberals in Ontario. The Conservatives picked up a few points in the region, which helped them retain Leeds–Grenville–Thousand Islands–Rideau Lakes and Lanark–Frontenac, ridings that would not normally be in any danger.
Here again the NDP slid to near irrelevancy with just 3.4% of the vote, with big decreases in Kingston and the Islands and Algonquin–Renfrew–Pembroke that largely went to the Liberals. The PPC dropped nearly six points to just 0.3%.