About this Ontario poll from Mainstreet Research
This Ontario poll was fielded by Mainstreet Research in June 2025, with a middle field date of June 25, 2025. The poll collected data from a total sample of n=923 Ontario respondents via IVR technology (automated calls).
The margin of error for an online sample is not applicable.
For comparison purposes, a random sample of this size would yield a margin of error [moe] of ±3.2%, 19 times out of 20 (for entire sample only) around the 50%-mark.
The regional breakdown of this poll was not made publicly available.
If we compare these national numbers with the previous poll from Mainstreet Research (February 2025), the Ontario PC Party loses three points from 44% to 41% (variation similar to moe), the Ontario Liberal Party climbs two points from 30% to 32% (variation smaller than moe), and the Ontario NDP remains stable at 17%.
You can read more information on this poll here.