Up until 1978 the two publishing houses of Aschehoug and Gyldendal, Norway's two largest, had published Aschehougs konversasjonsleksikon and Gyldendals konversasjonsleksikon, respectively. The respective first editions were published in 1907–1913 (Aschehoug) and 1933–1934 (Gyldendal).
The slump in sales for paperbased encyclopedias around the turn of the 21st century hit Kunnskapsforlaget hard, but a fourth edition of the paper encyclopedia was secured by a grant of 10 million Norwegian kroner from the foundation Fritt Ord in 2003. The fourth edition consisted of 16 volumes, a total of 12,000 pages and 280,000 entries.
|Store norske leksikon|
The complete last edition of Aschehoug og Gyldendals Store norske leksikon
On 12 March 2010 Kunnskapsforlaget announced that they would close the online encyclopedia because of lacklustre sales and failing revenue. It was also announced that the articles would not be given to the Wikimedia Foundation, with chief-editor Petter Henriksen stating that: "It is important that the people behind the articles remain visible".
In 2011, the foundations Fritt Ord and Sparebankstiftelsen DNB aquired the encyclopedia, hired Anne Marit Godal as the new chief editor and established a new organisation, assisted by the Norwegian Academy of Science and Letters and Norwegian Non-Fiction Writers and Translators Association. In 2014 the Great Norwegian Encyclopedia Association took over the encyclopedia; the members of the association were all the Norwegian universities and other non profit organisations. In 2016 Erik Bolstad became the new chief editor.
As of 2018 the SNL has around 200,000 articles online, updated by approximately 750 affiliated academics. The SNL accepts contributions from users, but all changes to the articles are verified by a topic expert before publication. The online encyclopedia are among the most-read Norwegian published sites, with around 2 million unique visitors per month.