ウィリアム・ヘムズリー（William Botting Hemsley、1843年12月29日 - 1924年10月7日）はイギリスの植物学者。王立植物園（キューガーデン）で働いた。

 来歴 
サセックスのイースト・ホースリーで生まれた。1860年からキューガーデンで働き、1889年に王立協会のフェローに選ばれた。トーマス・チーズマン（Thomas Frederick Cheeseman）と共著の、『ニュージーランドの植物の図説』（Illustrations of the New Zealand flora）やダニエル・オリバー（Daniel Oliver）の『熱帯アフリカの植物』の"Rhamneae"（クロウメモドキ連 ）や"Campanulaceae" （キキョウ科）、 "Scrophulariaceae" （ゴマノハグサ科）、"Balanophorsceae"（ツチトリモチ科）などの章を執筆した。

ウリ科の属名ヘムスレイア属 Hemsleyaに献名されている。

 著書 
 "Report on the scientific results of the voyage of H.M.S. Challenger during the years 1873-1876" ; Botany ; vol. 1, pt. 3, London, Edinburgh, Dublin, -1885. 
ウィキスピーシーズの記事。
 マイクロフィッシュ版。 Report on the botany of Juan Fernandez, ..., IDC Publishers, . IDC order no. 110.
 タイトル別名 Report on the botany of Juan Fernandez : the south-eastern Moluccas, and the Admirality Islands ; Report on the scientific results of the voyage of H.M.S. Challenger during the years 1873-1876
 (Linden, Jean Jules、André, Edouard François 編) The illustration horticole : an illustrated monthly review of new and interesting plants with their descriptions, history and culture, [s.n.]. 1874, .
 Diagnoses Plantarum Novarum (1878–1880)　ウィキスピーシーズの記事。

 共著 
 Biologia Centrali-americana … Botany (5巻), 1879–1888, (online)
 Botany, Published for the editors by R. H. Porter and Dulau. 1879. 〈Biologia Centrali-Americana〉 / F. Ducane Godman、Osbert Salvin 編, . (Hooker, Joseph Dalton, Sir、Thiselton-Dyer, William T. (William Turner) と共著)

 Handbook of hardy trees, shrubs, and herbaceous plants : containing descriptions, native countries, etc. of a selection of the best species in cultivation, together with cultural details, comparative hardiness, suitability for particular positions, etc. : based on the French work of Messrs. Decaisne and Naudin entitled 'Manuel de l'amateur des jardins,' and including the original woodcuts by Riocreux and Leblanc, Estes & Lauriat. 1873, . (Decaisne, Joseph、Naudin, Charles、Rand, Edward Sprague と共著) 
 Handbook of hardy trees, shrubs, and herbaceous plants : containing descriptions, native countries, etc. of a selection of the best species in cultivation, together with cultural details, comparative hardiness, suitability for different situations, etc. : based on the French work of Messrs. Decaisne and Naudin entitled "Manuel de l'amateur des jardins" and including the original woodcuts by Riocreux and Leblanc, Longmans, Green. 1877, . (Decaisne, Joseph、Naudin, Charles と共著) 
 Enumeration of all Plants known from China, 1886、1895. (Francis Blackwell Forbesと 共著)
 Illustrations of the New Zealand flora, John Mackay, 1914, . (Cheeseman, T. F. (Thomas Frederick)、Smith, Matilda と共著)
 Flora Simlensis : a handbook of the flowering plants of Simla and the neighbourhood, Thacker, 1921, . (Collett, Henry と共著)
 Flora Simlensis : a handbook of the flowering plants of Simla and the neighbourhood, Bishen Singh Mahendra Pal Singh. 1980, . (Collett, Henry と共著)
 A sketch of the vegetation of British Baluchistan with descriptions of new species. Bishen Singh Mahendra Pal Singh, 1978, . (Lace, J. H. (John Henry) と共著)
 Collection of plants from Upper Burma and the Shan states, Bishen Singh Mahendra Pal Singh. 1979, . (Collett, Henry と共著)
 An enumeration of all the plants known from China Proper, Formosa, Hainan, Corea, the Luchu Archipelago, and the Island of Hongkong : together with their distribution and synonymy, O. Koeltz Science Publications, 1980, , . (Forbes, Francis Blackwell と共著)