The crash happened Tuesday evening on Highway 550 near Duchess, about 200 kilometres east of Calgary.
RCMP say the 19-year-old victim, who was the lone occupant of the car, was heading east toward the small community when her vehicle slammed into the horses.
They say the animals were in the middle of the road, and that weather conditions were clear at the time while the road surface was dry.
The woman, who was from Duchess, died at the scene but police have not released her name.
There is no word on whether the horses survived the impact.