The unknown assailants dropped a gasoline-soaked piece of cloth and a fuel canister in the courtyard of the Fatih mosque based in the town of Stadtallendorf.
No one was injured in the attack as the chairman of the Turkish Islamic community managed to extinguish the fire after a woman noticed it.
The arson assault took place two hours after the end of the evening prayer, according to the report.
Mosques across Germany have been repeatedly targeted in Islamophobic attacks in recent years.
