Sten Mauritz Carl Lewenhaupt (27 February 1882 – 7 September 1969) was a Swedish nobleman, diplomat and archivist.

In 1809, he was promotad attaché of the Ministry for Foreign Affairs of Sweden and published registers and collections of treaties, including editor of Utrikesdepartementets kalender, for many years.

His sense for cadastral data made Svenska högre ämbetsmän från 1634 an extraordinary resource to historians and other researchers.

He was also an archivist, and later librarian, of the Ministry for Foreign Affairs, and was made head of the Office of Encipherment in 1919.

First on 13 August 1933 with Signe Wilhelmina Lindgren (1888–1945), daughter of Karl Johan Lewenhaupt (born c. 1823–1883).