| Named By: | Richard Owen in 1841 |
| Time Period: | 55-45 Ma |
| Location: | Across the Northern hemisphere, But best known from Western Europe and North America |
| Size: | Average 60 centimetres long |
| Diet: | Herbivore |
| Fossil(s): | Hundreds of specimens |
| Classification: | | Chordata | Mammalia | Perissodactyla | Palaeotheriidae | |
| Also known as: | | Eohippus | |
Hyracotherium ( HY-rak-o-THEER-ee-am; "hyrax-like beast") is an extinct genus of very small (about 60 cm in length) perissodactyl ungulates that was found in the London Clay formation. This small, dog-sized animal was once considered to be the earliest known member of Equidae before the type species, H. leporinum, was reclassified as a palaeothere, a perissodactyl family basal to both horses and brontotheres. The remaining species are now thought to belong to different genera, such as Eohippus, which had previously been synonymised with Hyracotherium.