Jens Jonas Schroeter Jansen (19 September 1900 – 26 October 1975) was a Norwegian archivist.
He was born in Bærum as a son of vicar Jens Jonas Elstrand Jansen (1844–1912) and Jenny Therese Schroeter (1863–1942), and brother of Einar Jansen.
[1] He finished his secondary education in 1918 and graduated from the Royal Frederick University with the cand.philol.
He is also known as a co-editor of the biographical dictionary Norsk Biografisk Leksikon from 1954.
He chaired the union Arkivarforeningen from 1938 to 1947 and was a board member of Kjeldeskriftfondet from 1940 to 1945 and of the Norwegian Genealogical Society from 1949.