Lagomorpha is an order of placental mammals, comprising the rabbits, hares, and pikas. Members of this order are called lagomorphs. It currently comprises 93 extant species, which are grouped into 12 genera. Lagomorphs live on every major landmass except Antarctica, and in a variety of habitats, especially forests, grasslands, shrublands, and rocky areas. They are generally small in size and come in two main groupings of body plans, the larger rabbit group and smaller pika group, ranging overall from the 11 cm (4 in) long Gansu pika to the 76 cm (30 in) long desert hare. The domestic rabbit subspecies of the European rabbit has been domesticated, resulting in a worldwide distribution.
Lagomorpha is divided into two families: Leporidae, comprising the rabbits and hares; and Ochotonidae, or the pikas. The 64 extant species of Leporidae are divided into 11 genera, though the majority of the species are placed into Sylvilagus (cottontail rabbits) and Lepus (hares); the 29 extant species of Ochotonidae are grouped into a single genus, Ochotona. The exact organization of the species is not fixed, with many recent proposals made based on molecular phylogenetic analysis. No lagomorph species have recently gone extinct, though some species are endangered and the riverine rabbit is critically endangered.