Reiulf Steen is a Norwegian politician who was active in the Norwegian Labour Party from 1958 to 1990. He has served as the party's chairman from 1975 to 1980.

Steen was born August 16, 1933 in Hurum, Norway. He was elected leader of the regional Labour Party affiliate at age 14. He started out his professional career as a factory worker but soon took a job as a journalist in the newspaper Fremtiden, in Drammen. He rose quickly through the ranks of his party, and served in various ministerial positions. He maintained a long-standing interest in Latin America and was appointed Norway's ambassador to Chile.

In later years, his memoirs and personal recollections have affected public opinion. He has related accounts of his own psychiatric problems, difficulties within the Labour Party, and other contemporary issues.