Negotiations impact about 43-hundred unionized workers in St. Catharines, Oshawa and Woodstock.
Canada's largest private sector union will open talks today with General Motors.
This comes after Unifor members voted to accept the union's new three-year labour agreement with Ford.
But the 54%t favourable vote was in stark contrast to support for the previous contract, which was 81%.
Experts are speculating that reaching deals with G-M and Stellantis could prove more challenging, especially since those companies are bigger and more profitable.
Unifor's negotiations with G-M cover about 43-hundred unionized workers at three sites in St. Catharines, Oshawa and Woodstock.

Mayors Welcome Change, With Condition
Mayor Hopes for Governance Reconsideration
Weekend RIDE Stops a Few Drivers
Rock Scaling Disrupts Traffic
Thorold Wants Beaverdams Traffic Control
Opinion Wanted on Ontario Street Rebuild
Habitat for Humanity Looks for Donations
Burdett Sisler Dies at 110