Eileen Forrester Agar RA (1 December 1899 – 17 November 1991) was an Argentine-British painter and photographer associated with the Surrealist movement.

Before attending school, she grew up in her family villa, Quinta la Lila, learning from her nanny and a French governess.

The music master, Horace Kesteven, introduced Agar to various artists, in particular, Charles Sims, who exposed her to some of Paul Nash's early works.

That infuriated her mother and, after an argument with her parents, Agar noted in her diary that she got up early, ate lunch with her sisters, packed her bags, and departed from Paddington station.

She left a note for her parents stating that she was on her way to Truro and St Mawes, where she would stay with family friends, the De Kays.

From 1921 to 1924, she studied part-time under Henry Tonks at the Slade School of Fine Art in London, alongside Rex Whistler, Cecil Beaton, and her first husband, Robin Bartlett.

[4] Agar resisted the wealthy lifestyle she was privy to and pointedly refused to make use of the Rolls-Royce her parents sent to pick her up from the Slade each day.

[7] In 1926, Agar met a Hungarian, Joseph Bard, with whom she would spend the next 50 years, and whose passion for jewels she would integrate into her artistic practice.

In 1928, Agar and Bard moved to Paris, where she met the Surrealists André Breton and Paul Éluard, with whom she had a friendly relationship.

Agar describes her piece in her memoir as her "first attempt at an imaginative approach to painting and although the result was surreal, it was not done with that intention".

In her 1928 diary entry, she described the various images in her painting as showing Greece as the meeting place of Judaeo-Egyptian and Greco-Christian culture, followed by the words "the Judaeo-Greco pillar", as if it were a note to bear in mind and to later be developed.

Reviewing it in The Burlington Magazine, Frances Spalding said the book "with its first-hand experience and vivid vignettes of Picasso, Eluard, Henry Moore and many others, makes an important contribution to surrealist literature"[8] Agar was one of the five artists featured in the television series Five Women Painters made in 1989 by the Arts Council and Channel 4, with an accompanying book published by Lennard.

Goshka Macuga's 2007 exhibition, part of the "Art Now" series at Tate Britain, used material drawn from Eileen Agar's archive.