James Petiver (c. 1665 – 20 April 1718) was a London apothecary, a fellow of the Royal Society as well as London's informal Temple Coffee House Botany Club, famous for his study of botany and entomology.
Born in Hillmorton, Warwickshire where his father was a haberdasher, he studied at Rugby Free School. He became an apprentice to an apothecary Charles Feltham in London on 5 June 1677, and was made a freeman of the Society of Apothecaries on 6 October 1685, later supplying medicine to St. Bartholomew's Hospital. He is buried at St Botolph Church.
Petiver visited the Netherlands in 1711 to study with Dutch entomologists. He recorded many English folk-names for butterflies, also coining some himself, and wrote some of the first butterfly books that used English names in addition to Latin. He himself was not very proficient in Latin although he was a member of several scholarly societies and an educated gentleman. He named the white admiral butterfly, and gave the name fritillary to another group of butterflies after the Latin word for a chequered dice box. He called skippers "hogs", swallowtails "Royal Williams", walls as "Enfield Eyes" and marbled whites as "Half-Mourners".
Petiver received many specimens, seeds and much other material from correspondents in the overseas, including Samuel Browne in Madras or the Czech Jesuit Georg Joseph Kamel in Manila. After his death, his collections were purchased by Sir Hans Sloane for £4000, and some of it is now in the Natural History Museum in London.