Officers were called to the scene just off the A91 road in the village of Blairlogie, near Stirling, on Sunday afternoon.
It has been described as an "ongoing multi-agency operation" and police are working to establish the cause of death. No further details have been released about the deceased.
Officers remain at the scene and drivers are being advised to avoid the area.
A police spokesman said: "Police in Forth Valley can confirm that they are involved in an ongoing multi-agency operation in Blairlogie in relation to a body, which was found within a vehicle.
"Police and other emergency responders are working to establish the cause of death, and due to the continued activity of the emergency services motorists are advised to avoid the area if possible."