Ginkgo is a genus of highly unusual non-flowering plants with one extant species, G. biloba, which is regarded as a living fossil.

The Ginkgo is a living fossil, with fossils recognisably related to modern Ginkgo from the Permian, dating back 270 million years. The most plausible ancestral group for the order Ginkgoales is the Pteridospermatophyta, also known as the "seed ferns," specifically the order Peltaspermales. The closest living relatives of the clade are the cycads, which share with the extant G. biloba the characteristic of motile sperm. Fossils attributable to the genus Ginkgo first appeared in the Early Jurassic, and the genus diversified and spread throughout Laurasia during the middle Jurassic and Early Cretaceous. It declined in diversity as the Cretaceous progressed, and by the Paleocene, Ginkgo adiantoides was the only Ginkgo species left in the Northern Hemisphere while a markedly different (and poorly documented) form persisted in the Southern Hemisphere. At the end of the Pliocene, Ginkgo fossils disappeared from the fossil record everywhere except in a small area of central China where the modern species survived. It is doubtful whether the Northern Hemisphere fossil species of Ginkgo can be reliably distinguished. Given the slow pace of evolution and morphological similarity between members of the genus, there may have been only one or two species existing in the Northern Hemisphere through the entirety of the Cenozoic: present-day G. biloba (including G. adiantoides) and G. gardneri from the Paleocene of Scotland.