Euphorbia is a genus of plants belonging to the family Euphorbiaceae. Consisting of 2008 species,Euphorbia is one of the largest and most diverse genera in the plant kingdom, along with Rumex and Senecio. Members of the family and genus are sometimes referred to as Spurges. Euphorbia antiquorum is the type species for the genus Euphorbia; it was described by Carl Linnaeus in 1753 in Species Plantarum. The genus is primarily found in the tropical and subtropical regions of Africa and the Americas, but also in temperate zones worldwide. Succulent species originate mostly from Africa, the Americas and Madagascar. There exists a wide range of insular species: on the Hawaiian Islands where spurges are collectively known as "akoko", and on the Canary Islands as "tabaibas".

The common name "spurge" derives from the Middle English/Old French espurge ("to purge"), due to the use of the plant's sap as a purgative.

The botanical name Euphorbia derives from Euphorbus, the Greek physician of king Juba II of Numidia (52–50 BC – 23 AD), who married the daughter of Anthony and Cleopatra. He wrote that one of the cactus-like Euphorbias was a powerful laxative. In 12 B.C., Juba named this plant after his physician Euphorbus in response to Augustus Caesar dedicating a statue to Antonius Musa, his own personal physician. Botanist and taxonomist Carl Linnaeus assigned the name Euphorbia to the entire genus in the physician's honor.