| Named By: | Discovered by Kan Chuen Pao in 1923, Henry Fairfield Osborn wrote the description in 1924 |
| Time Period: | Middle Eocene, 48-41 Ma |
| Location: | Mongolia |
| Size: | Total size uncertain due to lack of remains. Skull is 83 centimetres long |
| Diet: | Carnivore |
| Fossil(s): | Skull |
| Classification: | | Chordata | Mammalia | Artiodactyla | |
Andrewsarchus () is an extinct genus of mammal that lived during the middle Eocene epoch in what is now Inner Mongolia, China. Only one species is usually recognized, A. mongoliensis, known from a single skull of great size discovered in 1923 during the expeditions to central Asia by the American Museum of Natural History (AMNH). Generally classified as a mesonychid since its original description, most recent studies classify it as an artiodactyl, in one study specifically, as a member of the clade Cetacodontamorpha, closely related to entelodonts, hippos and whales.