Sonja Mjøen (25 December 1898 – 25 February 1993) was a Norwegian actress. She was born in Christiania, a sister of Fridtjof Mjøen and Jon Lennart Mjøen, and was married to journalist Axel Kielland. She made her stage debut at Trondhjems nationale Scene in 1924, in Hjalmar Christensen's play Din egen herre. Her film debut was in 1927. She published the books Da mor var ung in 1975 and Elsk din skjebne in 1977.