Irene Manton, FRS FLS (born Irène Manton; 17 April 1904, in Kensington – 13 May 1988) was a British botanist who was Professor of Botany at the University of Leeds. She was noted for study of ferns and algae.

Irene Manton was the daughter of dental surgeon, George Manton and embroideress and designer, and descendant of French aristocracy, Milana Manton (née D'Humy). Her first name was originally pronounced and spelled in the French manner; but at 18 she dropped this and opted for "Irene". Her sister was the entomologist Sidnie Manton FRS. She was educated at the Froebel Demonstration School and St. Paul's Girls' School, Hammersmith. While still in school she read Edmund Beecher Wilson’s (1902) The Cell in Development and Heredity prompting an early interest in chromosomes.

In 1923 Manton attended Girton College, Cambridge. She found Cambridge unsatisfying, in part because the university as a whole was not yet welcoming of women, and later went on to study with Gustaf Otto Rosenberg in Stockholm. Manton obtained a lecturing position at the University of Manchester in December 1928. In June 1930 she received her PhD, with her thesis being on Cruciferae. She had to apply for special permission to continue her PhD studies away from Cambridge when she obtained the position at Manchester.

Much of her academic career was spent at the University of Leeds where she was Professor of Botany from 1946 until 1969 and Professor Emeritus thereafter and where her focus was on ferns and algae. The work with ferns addressed hybridisation, polyploidy, and apomixis and led to her 1950 book, Problems of cytology and evolution in the pteridophyta. As well as engaging chromosomes for the purposes of evolutionary investigation, Manton carried out research into gross morphological structure using the ultraviolet microscope. This venture proved to be an important stepping stone to her later fine structural research of the cell.

Her work on the algae was notable for its use of the electron microscope and her cytological work became known worldwide for the structure of cilia and flagella she revealed.

Irene Manton bequeathed her collection of modern and oriental art to the University of Leeds. Many of these pictures hung on the walls of Botany House in the University of Leeds during her career there.

Manton was a co-supervisor (with David Jennings) for then-PhD student Evan Benjamin Gareth Jones, who graduated in 1963 and later became a notable mycologist, and of Patrick Brownsey, who became Curator of Botany at the National Museum of New Zealand. She also taught Mary Gibby while Gibby was an undergraduate at the University of Leeds.

In 1969 Manton shared the Linnean Medal with Ethelwynn Trewavas.