| Named By: | Loomis in 1936 |
| Time Period: | Oligocene-Miocene |
| Location: | USA |
| Size: | Estimated around 39 kilograms in weight |
| Diet: | Carnivore |
| Fossil(s): | Several specimens |
| Classification: | | Chordata | Mammalia | Carnivora | Caniformia | Amphicyonidae | Temnocyoninae | |
Mammacyon is an extinct genus of medium-sized amphicyonid caniformian carnivoran mammals endemic to North America during the Oligocene to Miocene living from 30.8--20.6 Ma and existed for approximately 10.2 million years.