Pluscarden Road, near Elgin was closed following the incident, which took place around 1.30pm.
The man was airlifted to Aberdeen Royal Infirmary and the route remains shut.
A Police Scotland spokeswoman said: “Pluscarden Road remains closed following a crash involving a motorbike and a tractor.
“Road collision investigators are conducting enquiries to establish what has happened. The male motorcyclist has been airlifted to Aberdeen Royal Infirmary, the driver of the tractor is uninjured.”