Robert Bentley (25 March 1821 – 24 December 1893) was an English botanist. He is perhaps best remembered today for the four-volume Medicinal Plants, published in 1880 with Henry Trimen and containing over three hundred hand-colored plates by botanist David Blair.

Robert Bentley was born in Hitchin, Hertfordshire in 1821. While apprenticed to a pharmacist in Tunbridge Wells, he developed an interest in botany. He subsequently studied medicine at King's College London, and became a Member of the Royal College of Surgeons in 1847 and a Fellow of the Linnean Society of London in 1849. ^[1]

Bentley served as botany lecturer at the Medical School of the London Hospital, and in 1859 became Professor of Botany at King's College London. ^[1]

In 1874, Bentley was elected a Fellow of the Royal Pharmaceutical Society of Great Britain, and he served as joint editor of the British Pharmacopeia of 1885.^[1]

Bentley died at his home in Warwick Road, Kensington, on 24 December 1893, and was buried at Kensal Green cemetery.^[1]

• A Manual of Botany: including the structure, functions, classification, properties, and uses of plants, etc. (1861), at Google Books
• Characters, Properties, and Uses of Eucalyptus (1874)
• Botany (1875, London)
• Medicinal Plants: being descriptions with original figures of the principal plants employed in medicine and an account of the characters, properties, and uses of their parts and products of medicinal value - written with Henry Trimen (1880, London, Churchill)
• The Student's Guide to Structural, Morphological, and Physiological Botany (1883, London)
• A Text-book of Organic Materia Medica, comprising a description of the vegetable and animal drugs of the British Pharmacopoeia, with other non-official medicines, etc. (1887)
• Physiological botany: an abridgement of The students’ guide to structural, morphological, and physiological botany. Appleton & Comp. New York 1886 (Digitized).