Sir Arthur William Hill KCMG FRS FLS (11 October 1875, in Watford – 3 November 1941), was Director of the Royal Botanic Gardens, Kew and a noted botanist and taxonomist.
The only son of Daniel Hill, he attended Marlborough College where his interest in natural history was encouraged by the classical master and entomologist, Edward Meyrick. Hill went on to King's College, Cambridge, where he came under the influence of Marshall Ward and Walter Gardiner, acquiring an MA and DSc.
His numerous field trips started with the expedition of the English geographer, William Bisiker FRGS, to Iceland in 1900. This was followed by exploration of the Andes in Bolivia and Peru in 1903, sparking an interest in cushion plants which was to last throughout his life, and the Caribbean in 1911.
In 1907 he joined Kew as Assistant Director under Sir David Prain, and started contributing to the floras of Africa and India. In 1922 he succeeded Prain as Director. With grants from the Empire Marketing Board, Hill was able to send botanists all over the world, himself visiting Australia, New Zealand, Malaya, Rhodesia, East Africa, India, Cyrenaica and the West Indies. His interests were not confined to taxonomy, but extended to economic botany, of which he was an enthusiastic proponent, and all the other activities of Kew. He managed a large number of changes in the Gardens, despite having to operate in the post-war austerity climate. Some of his greatest successes were in building, renovating, and extending glasshouses, being responsible for the new Rhododendron House in 1925–26, an improved Economic House in 1930 and the South African Succulent House in 1936.