Knud Geelmuyden Fleischer Maartmann (1821–1888) was a Norwegian politician.
He was elected to the Parliament of Norway in 1865, representing the urban constituency of Flekkefjord.
His son Harald Sigwart Maartmann (1855 - 1926) become the first director of Ringnes Bryggeri in 1901.
He was the grandfather of Knud Maartmann Ringnes.
This article about a Norwegian politician born in the 1820s is a stub.