Knut Buen (born 1948) is a Norwegian fiddler, composer, folklorist and publisher. He was born in Kongsberg; the son of folk musician Anders Buen and Margit Tjønn, and is brother of Hauk Buen and Agnes Buen Garnås. He won the national music contest Landskappleiken in 1983 and 1986, and is known for his collection of traditional songs and melodies. He received Spellemannprisen in 1992 for the album Fykerud'n (in cooperation with Hauk Buen), and in 1994 for the album Bjølleslåtten (together with Kåre Nordstoga and Leif Rygg). He has been running the publishing company Buen kulturverkstad and the record company Nyrenning. He was decorated Knight, First Class of the Order of St. Olav in 1999.
He plays on the Norwegian folk metal band Hardingrock, along with Ihsahn and Starofash.