Police in the Outaouais say the crash happened shortly after 9:30 a.m. Friday in Low, Que., north of Gatineau.
Police said the car was heading north when the driver of the car lost control and hit the truck.
Firefighters had to extricate the driver from her car before paramedics took her to the Hull hospital.
They say she suffered life-threatening injuries.
The truck driver was taken to hospital with minor injuries.
Police are investigating.