The woman was driving with her five passengers along road 71 near Snöån in Vansbro in Dalarna when she crashed with the elk late on Saturday evening, local media reports.
The woman, who was in her twenties, died of her injuries in hospital later on Sunday morning.
Four of the other five male passengers in the car are reported to have suffered minor injuries and were discharged from Falu hospital on Sunday morning. The fifth man has been taken to Mora hospital and it is as yet unclear as to the severity of his injuries.
The road was closed while police and emergency services conducted their work.