Siri Nilsen (born 1985 Oslo, Norway) is a Norwegian singer, songwriter, musician, and voice actress. She is the daughter of Norwegian folk singer Lillebjørn Nilsen and an American mother, Shari Nilsen. She has released two albums: Vi som ser i mørket (We Who See in the Dark) in 2009, and Alle snakker sant (They All Speak the Truth) in November 2011. Music critics have expressed similar appraisal of her music, noting the sincerity of her song writing and the clarity and range of her voice, characterized as "unique" and "beautiful". Nilsen often accompanies her singing with a ukulele, which she plays in a fingerpicking style.

Nilsen made her debut as a stage artist in 2007 and has since performed in venues ranging from small clubs to larger concert halls and festivals. In December 2011, she was nominated for a Norwegian Grammy in the category of Best Female Artist for her latest album. Nilsen has had a career for several years as a voice actress, dubbing character roles into Norwegian for several feature films and television, mostly animation.