The incident occurred around 9 p.m. on the eastbound QEW near Burloak Drive.
Oakville firefighters said the tractor trailer was “fully involved” with flames and black smoke shooting out of the vehicle.
No injuries were reported but the OPP have blocked the right lanes for the investigation and clean-up.
“Stuck in the mess for nearly 30 minutes now,” said Nicole Brennan, a passenger in a vehicle being driven by her mom on the QEW, who reached out to InsideHalton.com to report the incident.
The lanes reopened early Thursday.
Anyone with information can call the OPP at 905-278-6131.