Quebec provincial police said three adults and a child were killed when the car they were travelling in was struck by a pickup truck that swerved into their lane.
A fifth occupant of the car, a toddler, was transported to hospital in Mont-Laurier but his injuries are not considered life-threatening.
The two occupants of the truck were also injured and taken to hospital.
The collision happened near Lac Larouche, 160 kilometers north of Mont-Laurier.
The highway where the accident happened is the main link between the Laurentians and the Abitibi-Temiscamingue region.
Note to readers: This is a corrected story. The original listed an incorrect date