Lumsden RCMP, local paramedics and Regina Beach Fire Department all responded to the crash, which happened on Township Road 211 at about 2:30 a.m.
The woman was found dead outside the vehicle, while a second occupant, a 54-year-old man, was located inside the vehicle.
The man was taken to a Regina hospital for medical treatment.
RCMP believe the lone SUV was heading westbound before rolling into the ditch.
An investigation is being done by RCMP traffic analysts, which is expected to take several months to complete.