Strophanthus is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1802. It is native primarily to tropical Africa, extending to South Africa, with a few species in Asia from southern India to New Guinea and southern China. The genus name is a compound of the Greek words στροφος (strophos) "twisted" and ανθοσ (anthos) "flower", in reference to the corolla lobes which, in some species - notably S. petersianus - resemble long twisted ribbons or threads and can reach a length of 30–35 cm. This trait, in addition to colouring involving combinations of bright pinks, purples and oranges, combine to make the flowers among the most ornamental in the plant kingdom.

Apocynoideae is a subfamily of the flowering plant family Apocynaceae, also called the 'dogbane' or milkweed family, containing about 860 species across 78 genera. Several are of pharmacological interest; Strophanthus has furnished highly effective arrow poisons, due to their cardiac glycoside content. Apocynoideae also includes many popular landscaping and ornamental species, one of the best-known, and most infamous, being the oleander ; the subfamily also contains remarkable pachycaul genera like Adenium and Pachypodium.