The accident that killed Const. Katia Hadouchi, 23, happened just before 7 p.m. ET in Saint-Ambroise-de-Kildare, about an hour north of Montreal.
Hadouchi was responding to a domestic violence call when she lost control of the patrol car on Kildare Road and swerved.
The officer was transported to hospital in critical condition, but died overnight.
She had worked for the Sureté du Québec for two years and was alone in the car. No other vehicles were involved.
Collision investigators were called to the scene to try to determine the cause of the crash. SQ Sgt. Christine Coulombe said it's unclear if speed was a factor.
"All of those elements will be studied as the investigation [progresses]," she said.