Ketil Bjørnstad (born April 25, 1952 in Oslo) is a Norwegian pianist and composer. Initially trained as a classical pianist, Bjørnstad discovered jazz at a young age and has enthusiastically embraced the emergence of 'European jazz'.

Although perhaps best known as an artist on the ECM record label, Bjørnstad is also an accomplished writer, having published some 20 books (predominantly novels) and a number of poetry and essay collections.

Ketil Bjørnstad made his debut with the Oslo Philharmonic in 1969, 16 years old, playing Bartok nr. 3. Listening to Miles Davis' "In a silent way" made him want to create his own music. Thanks to the very lively milieu around the Oslo music spot "Club 7" in the seventies, he met with poets, painters, jazz-musicians, and was encouraged to find his own style. Onthe first recording in 1973, called Åpning, he played with the drummer Jon Christensen for the first time. Jon was extremely important for Ketil, playing on three more albums, including the two The Sea albums for ECM.

Among Ketil Bjørnstad’s most important musical influences are Bach, Ravel, Prokofiev, Stravinskij, Miles Davis, Thelonius Monk and folk music. In his time he has collaborated with some of Scandinavia’s most distinguished folk- and rock-singers, like Ole Paus and Cornelis Vreeswijk. In the classical milieu he has collaborated much with the mezzo-soprano Randi Stene and the viola player Lars Anders Tomter. For his efforts he has had the honour of receiving a Norwegian Grammy award.

He has frequently collaborated with other ECM artists, including American cellist David Darling, drummer Jon Christensen, and guitarist Terje Rypdal.