Knut Nystedt (born 3 September 1915) is an orchestral and choral composer.

Nystedt was born in Kristiania (now Oslo), Norway, and grew up in a Christian home where hymns and classical music were an important part of everyday life. His major compositions for choir and vocal soloists are mainly based on texts from the Bible or sacred themes. Old church music, especially Palestrina and Gregorian chants, have had a major influence on his compositions.

He has studied with Aaron Copland, among others. Nystedt was organist in Torshov kirke (Torshov Church) in Oslo from 1946 to 1982 and taught choir conducting at the Universitetet i Oslo from 1964 to 1985.

Nystedt founded and conducted Det Norske Solistkor from 1950 to 1990. He also founded and conducted Schola Cantorum from 1964 to 1985. The choir Ensemble 96 has published «Immortal Nystedt» (2005). This CD has been nominated in two categories in the Grammy Awards 2007. This is the first Norwegian cd nominated in two categories. Also the first cd with a Norwegian composer nominated to Grammy. In 2005 he was honoured by several concerts around the world, celebrating his 90th birthday.

In 1966, the King of Norway made him Knight of the Order of St. Olav in recognition of his contributions to Norwegian music. And in 2002 the King of Norway made him Commander of St. Olav. He received Spellemannprisen 1978 for his album Contemporary Music From Norway. He received Norsk Kulturråds Musikkpris in 1980. «De Profundis» became the work of the year Norsk Komponistforening. Knut Nystedt became Professor Honorario by Mendoza University Argentina in 1991. In 2002 he received Årets Korpris from Norges Korforbund and Oslo bys Kunstnerpris (The Artists prize by the City of Oslo) (2005).

Most of his compositions (the score) are published by Norsk Musikforlag. His compositions are also published in several CDs in Norway and several other countries.