Gunnar Gunnarsson (18 May 1889 – 21 November 1975) was an Icelandic author who wrote mainly in Danish. He grew up, in considerable poverty, on Valþjófsstaður in Fljótsdalur valley and on Ljótsstaðir in Vopnafjörður. Despite great difficulties, he became one of the most popular novelists in Denmark and Germany.
Often considered one of the most important Icelandic writers, he wrote the novel Af Borgslægtens Historie (translated into English as Guest the One-Eyed), the first Icelandic writing ever made into a movie. He also wrote the autobiographical novel The Church on the Mountain (1923–28).
Gunnarsson lost his mother at an early age. Until the age of 18, he worked at the family farm and received his education attending small rural schools.
He started early writing poetry and short stories, and published his first books of poems at the age of 17. His family was too poor to provide him with traditional school education, but in 1907 he was finally able to enroll in the Askov Højskole, a Folk High School in Denmark. During the two years he spent there, he became determined to work as a writer. He also decided to write in Danish in order to reach a wider audience.
After several difficult years, Gunnarsson published his first novel in 1912, the first volume of Af Borgslægtens Historie (translated into English as Guest the One-Eyed). The second and third volumes were published the following year, the third one becoming a huge success in Denmark, and making his name as a writer. Four volumes appeared in this melodramatic epic relating the story of three generations of Icelandic farmers. Using the Cain and Abel theme, this is the story of two brothers, one of whom is a dreamer forced to choose between his creative longings and duty, while the other is evil incarnated in the first two volumes, but returns as the saint-like Guest the One-Eyed in the third, having atoned for his sins through service to others.
World War I brought a streak of pessimism into Gunnarsson's writings. Between 1920 and 1940 he published a number of essays on political and social issues, as well as on Nordic co-operation. He also gave numerous lectures in the Nordic countries and in Germany.
In 1939, Gunnarsson moved back to Iceland and first settled on Skriðuklaustur, a farm in East Iceland, where he built a house designed by German architect Fritz Höger. The house was later donated to the Icelandic state and turned into a museum in the memory of the writer. In 1948 Gunnarsson moved to Reykjavík, where he started translating his own works into Icelandic. This task was almost completed before his death in 1975.