John Henry Olsen AO OBE (21 January 1928 – 11 April 2023) was an Australian artist and winner of the 2005 Archibald Prize.

In 1957, Sydney business man, Robert Shaw and his then wife, Annette, supported by art critic Paul Haefliger sponsored Olsen to go to Europe and paint.

Olsen studied printmaking at Stanley William Hayter's Atelier 17 etching studio in Paris in 1957, followed by two years in Deià, Spain.

Olsen sent works back from Spain for his first solo exhibition at Macquarie Galleries in Sydney, 6–8 August 1958.

In the exhibition catalogue artist's statement, Olsen referred to Paul Klee's maxim of 'taking the line for a holiday.'

During this period, he was influenced by the Tachist artists Antoni Tàpies and Jean Dubuffet, the CoBrA group and Joan Miró.

Olsen's work is marked by a deep engagement with the Australian landscape and he lived for long periods in contrasting parts of the country and traveled widely in it.

Galbally identifies 'a perceptive piece of writing which stands out in the otherwise rather uneven text, [in which] we are told that:'[8] In European landscapes, man is always there, has been there, in the foreground, in the middle distance or in the background.

By contrast, in the Australian desert there seems to be no place for man at all; there seems no past, no present and no future; only an overwhelming withering of will and a numbing sense of despair.In 1960, Olsen painted Spanish Encounter which was acquired by the Art Gallery of NSW and exhibited at Terry Clune Galleries in Sydney.

Olsen's book My Salute to Five Bells which contains the artist's thoughts, diary entries and his original drawing for the work, was published by the National Library of Australia in 2015.

Olsen and his work on the mural are the subject of 2014 documentary The King Sun, directed by New Zealander Tony Williams.

His daughter Louise Olsen is a co-founder of cult Australian fashion jewellery label Dinosaur Designs.