Carlo Allioni (23 September 1728 in Turin – 30 July 1804 in Turin) was an Italian physician and professor of botany at the University of Turin. His most important work was Flora Pedemontana, sive enumeratio methodica stirpium indigenarum Pedemontii 1755, a study of the plant world in Piedmont, in which he listed 2813 species of plants, of which 237 were previously unknown. In 1766, he published the Manipulus Insectorum Tauriniensium.
In April, 1758 he was elected a Fellow of the Royal Society.
He was appointed extraordinary professor of botany at the University of Turin in 1760 and was also the director of the Turin Botanical Garden. The journal Allionia: bollettino dell' istituto ed orto botanico dell' università di Torino is named after him.
First Pehr Löfling and then Linnaeus named the New World herb genus Allionia (Nyctaginaceae) after Allioni.Per Axel Rydberg named the genus Allioniella (now Mirabilis), after him. Also named after him are: