Jónas Kristjánsson (10 April 1924 – 7 June 2014) was an Icelandic scholar and novelist, and one-time director of the Árni Magnússon Institute for Icelandic Studies. In this position, he played a crucial role in the return of Icelandic manuscripts to Iceland from Denmark, representing Iceland in negotiations with the Danish authorities from 1972-86.
Jónas was a teacher at the Samvinnuskóli from 1952-55, archivist at the National Archives of Iceland from 1957-63, and the director of the Árni Magnússon Institute for Icelandic Studies from 1972-94 (from which position he retired upon reaching the age limit). He spent 1978-79 in the UK. Jónas was also a member of the Norwegian Academy of Science and Letters. On May 31, 1991 he received an honorary doctorate from the Faculty of Humanities at Uppsala University, Sweden 
Jónas was best known for his works on Icelandic sagas, laying emphasis on their literary nature and working on several stylistic and syntactic problems. His 1972 doctoral thesis, Um fóstbræðra sögu presented new arguments about the dating of Fóstbræðra saga (arguing that it was not, as had previously been thought, relatively archaic, but relatively late).
Jónas was an important editor of Icelandic texts, namely Dínus saga drambláta, Viktors saga ok Blávus, and a number of sagas for the Íslenzk fornrit series, on whose editorial board he sat from 1979, including Svarfdæla saga, overseeing the editions of the biskupa sögur with Þórður Ingi Guðjónsson, and co-editing the 2014 edition of the Poetic Edda with Vésteinn Ólason.
Jónas wrote two historical novels, one of which, The Wide World, is set in Viking age North America, and he translated Will Durant's The Life of Greece and Arthur Miller's Death of a Salesman into Icelandic.
- R[ory] W. McT[urk], 'Jónas Kristjánsson 10 April 1924-7 June 2014', Saga-Book, 38 (2014), 113-15 (at 114).
- Fjársjóður Íslands Jónas Kristjánsson er að láta af störfum forstöðumanns, Morgunblaðið (in Icelandic), August 7, 1994 (long article on his career); R[ory] W. McT[urk], 'Jónas Kristjánsson 10 April 1924-7 June 2014', Saga-Book, 38 (2014), 113-15 (at 114).
- R[ory] W. McT[urk], 'Jónas Kristjánsson 10 April 1924-7 June 2014', Saga-Book, 38 (2014), 113-15 (at 113).
- "Gruppe 5: Filologi og språkvitenskap" (in Norwegian). Norwegian Academy of Science and Letters. Retrieved 10 January 2011.
- Davies, Karin. Iceland works to preserve its own folk tales, Lawrence Journal-World (Associated Press), November 17, 1991
- Second Viking site sought, The Record (Kitchener, Ontario), November 12, 2001 ("Prof Jonas Kristjansson an expert on the Norse sagas")
- New Clues Emerge on the Vikings' Voyage, The Boston Globe, February 4, 2000 ("Jonas Kristjansson one of Iceland's foremost scholars of the sagas")
- Jónas Kristjánsson, Um fóstbræðrasögu, Rit (Stofnun Árna Magnússonar á Íslandi), 1 (Reykjavík: Stofnun Árna Magnússonar, 1972)
- Jónas Kristjánsson (ed.), Dínus saga Drambláta, Riddarasögur, 1 (Reykjavík: Háskóli Íslands, 1960).
- Viktors saga ok Blávus, ed. by Jónas Kristjánsson, Riddarasögur, 2 (Reykjavík: Handritastofnun Íslands, 1964)
- Eyfirðinga s̨ogur, ed. by Jónas Kristjánsson, Íslenzk fornrit, 9 (Reykjavík: Hið íslenzka fornritafélag, 1956); cf. Svarfdælasaga, ed. by Jónas Kristjánsson, Rit Handritastofnunar Íslands, 2 (Reykjavík: Handritastofnun Íslands, 1966).
- Biskupa sögur, Íslenzk fornrit, 15-17 (Reykjavík: Hið Íslenzka Fornritafélag, 2002-3)