Einar Jansen (27 March 1893 – 13 December 1960) was a Norwegian historian, genealogist and archivist. He was born in Røyken as the son of priest Jens Jonas Jansen (1844–1912) and Jenny Therese Schroeter (1863–1942). He was a nephew of Jens Fredrik Schroeter. The family soon moved to Sandvika, and after finishing his secondary education in 1911, he enrolled in philology at the University of Kristiania, graduating with the cand.philol. degree in 1919. His final paper, Det suspensive lovvetos anvendelse i norsk konstitusjonel praksis, mixed history and constitutional law.