The Felids are a rapidly evolving family of mammals that share a common ancestor only 10-15 million years ago.^[16] Within this family, domestic cats (Felis catus) are part of the genus Felis, which is a group of small cats containing seven species.^[1][17] Members of the genus are found worldwide and include the Jungle Cat (Felis chaus) of southeast Asia, the African Wildcat (Felis silvestris lybica) and the Arabian Sand Cat (Felis margarita).^[18] All these cats share a common ancestor that probably lived around six million years ago in Asia.^[19] Within this genus, the closest relatives of domestic cats may be the African Wildcat and the Sand Cat,^[4] although the exact relationships are still controversial.^[19] As domestic cats are still closely related to wildcats, they can interbreed. This hybridization may pose a danger to the survival of wildcat populations, particularly in Scotland and Hungary.^[20]

The domestic cat was first classified as Felis catus by Carolus Linnaeus in the tenth edition of his Systema Naturae of 1758.^[2][21] However, domestic cats may be conspecific with (belong to the same species as) the Wildcat,^[21] which was classified as Felis silvestris by Schreber in 1777.^[22] This has resulted in mixed usage of the terms. Adding to the confusion, the domestic cat is sometimes considered to be a subspecies, F. s. catus, of the species F. silvestris.^[1][4] Wildcats have also been referred to as various subspecies of F. catus,^[22] but in 2003 the International Commission on Zoological Nomenclature fixed the name for Wildcats as F. silvestris.^[23] The most common name for the domestic cat remains F. catus, treating it as a separate species and following the convention of using the earliest (the senior) synonym proposed. Sometimes the domestic cat is called Felis domesticus,^[24] although this is not a valid scientific name.^[25]