Franz Ketterer (1676–1749) was an early Black Forest clockmaker from Schönwald im Schwarzwald in Germany. According to historians, he was one of several possible inventors of the cuckoo clock, although historical records from this period are scarce and often conflicting, and no cuckoo clock made by Ketterer can be found today. In his 1976 book Gerd Bender suggested that Franz Ketterer invented prototype cuckoo clocks in 1730. Others have suggested that the cuckoo clock was invented around 1735, 1737, or 1738.