Ernst Diesen (6 April 1913 – 14 November 1970) was a Norwegian revue and film actor and theatre director.

He was the son of Andreas Melchior Seip Diesen (1881–1958) and Sofie Elisabeth Aars Brodtkorb (1885–1968).

[1][4] Diesen studied at the theater school operated by Max Reinhardt in Berlin from 1932 to 1933.

He worked for the revue theatre Chat Noir from 1934 to 1942 and as theater director from 1950 to 1953.

[2] He also acted in several films, including the comedy films Bør Børson Jr. from 1938, Den forsvundne pølsemaker from 1941, Det æ'kke te å tru from 1942, Smuglere i smoking, and Pappa tar gull from 1964.