Hans Momsen (born 23 October 1735, Fahretoft – 13 September 1811, ibidem) was a North Frisian farmer, mathematician and astronomer.
Entirely without university studies he was able to solve complicated mathematical calculations and to construct astronomical devices, chronometers and other apparatus.
He gave lessons in mathematics to gifted students.
Moreover, he worked as a surveyor and built an organ for the church of Fahretoft.