The young boy was, for reasons unknown, run over by the family's own car on their property in Bålsta, in the Uppland region, north-west of Stockholm.
“It's an incredibly tragic accident in the family's own driveway,” police spokesman Christer Nordström told regional newspaper Upsala Nya Tidning on Sunday afternoon.
He said the parents had also been taken to hospital and had not yet been questioned.
“We still don't know how it happened. The child's parents are deeply shocked and have not been heard yet,” he said.
Police were called to the property shortly before 1pm on Sunday. Paramedics arrived soon thereafter, but were unable to resuscitate the boy.