Leiv Amundsen (30 May 1898 – 25 June 1987) was a Norwegian librarian and philologist.
He was born in Tjøme as a son of sailmaker Carl Amundsen (1851–1916) and Henrikke Elise Andersen (1857–1923).
He attended upper secondary school in Drammen, and worked at the University Library of Oslo at the same time as studying classical philology at the Royal Frederick University.
Amundsen was also secretary-general of the Norwegian Academy of Science and Letters from 1954 to 1961.
In 1976 he co-published the correspondence between Johan Ernst Gunnerus and Carl von Linné between 1761 and 1772.