| Named By: | R. H. Reinhart in 1959 |
| Time Period: | Miocene |
| Location: | Japan - Haraichi Formation, Haratajino Formation, Kurosedani Formation, Nagura Formation, Niwaya Formation, Satiama Prevecture, Sekinohana Formation, Tonokita Formation, Ushikubitoge Formation, Yamanouchi Formation. USA, California - Ladera Sandstone Formation, Monterey Formation, Oclese Sand Formation, Santa Margarita Formation, Skooner Gulch Formation, Temblor Formation, Topanga Formation. Mexico, Baja California - Torgugas Formation |
| Size: | Around 2.5 meters long |
| Diet: | Herbivore |
| Fossil(s): | Remains of multiple individuals |
| Classification: | | Chordata | Mammalia | Desmostylia | |
Paleoparadoxia ("ancient paradox") is a genus of large, herbivorous aquatic mammals that inhabited the northern Pacific coastal region during the Miocene epoch (20 to 10 million years ago). It ranged from the waters of Japan (Tsuyama and Yanagawa), to Alaska in the north, and down to Baja California, Mexico. Paleoparadoxia was about 2.2 m (7 ft 3 in) long.