Emergency services were called to Sainte-Brigide-d'Iberville shortly after 14:30 local time (18:30 GMT) on Saturday. They found the aircraft on fire and declared its occupants dead at the scene.
The victims have not yet been identified. Police say the helicopter was a private aircraft.
An investigation is led by the Major Crime Unit of the Sûreté du Québec and involves investigators from the Transportation Safety Board of Canada.
The crash site is near the Rang des Écossais road off Highway 10. Around an hour after the call, the fire was under control, but officials remained at the scene until about 22:00 local time.
Officials say identifying the victims may take a few days.
