Norwegian-Swedish painter and sculptor, who became known for his political art during the 1960s and 1970s. He mainly lived and worked in Stockholm, born 6 August 1932 on the farm Slettemark in Naustdal in Sogn og Fjordane, died 13 December 2008 in Stockholm.

Kjartan Slettemark trained as a switchboard operator and worked in Otta in Oppland 1952–1955. He then studied at the Statens håndverks- og kunstindustriskole 1956–1959 and for a short time at the Statens Kunstakademi in Oslo in 1959. Inga Bagge inspired him to move to Stockholm. He attended Gerlesborgsskolan 1960–1962 and further studied at the Royal Academy of Arts 1962–1965 for Lennart Rodhe and Erland Melanton. He worked, among other things, with concept art, video art and various more or less happening-type art, but also with acrylic painting. One of Slettemark's many art projects was the micronation of Kjartanistan, a non-territorial state that issued its own passports and where he himself was prime minister. He became a controversial name in Norway in 1965 after he exhibited in Oslo a work of art in a stand outside the Storting that described his disgust for President Nixon and the US involvement in the Vietnam War, the work was taken down by the Norwegian police after public demonstrations.

During the 1970s, he gained attention after traveling around Europe and the United States with a passport where the passport photo was a montage of a photograph of Richard Nixon and his own hair and beard, which he himself saw as a way to blur the line between art and life. When Malmö art gallery was inaugurated in 1975, Slettemark appeared as a barking poodle, with the aim of showing how artists often allow themselves to become lapdogs. His poodle costume is now in the collections of Moderna museet. He is also represented at, among others, the Gothenburg Art Museum, the Norrköping Art Museum and Nationalmuseum in Stockholm.

Haugar Vestfold Art Museum in Tønsberg has had a permanent exhibition of Kjartan Slettemark's work since 2003. He was one of the artists who received an artist's salary from the Swedish state. Together with Inga Bagge he exhibited in Värnamo in 1965 and together with Jan Håfström in Limhamn in 1966 and he participated in a large number of group exhibitions in Lidköping, Karlstad, Halmstad, Spånga, Norrtälje and Västervik, among others. His public works of a normal nature include a pair of painted windows for Hallstahammar's municipal building.

Kjartan Slettemarks became a Swedish citizen in 1966.