Sespia ("of Sespe Creek") is an extinct genus of oreodont endemic to North America. They lived during the Late Oligocene 26.3—24.8 mya, existing for approximately 1.5 million years.^[1] Sespia was cat to goat-sized and desert-dwelling.^{[citation needed]} The genus was closely related to the larger Leptauchenia.

Fossils of the best known species, the cat-sized S. californica, have been found California and are known from literally thousands of specimens. The largest species, the goat-sized S. ultima, is known from late Oligocene deposits in Nebraska. S. ultima was once placed in a separate, monotypic, genus as Megasespia middleswarti. Other species were once placed within Leptauchenia.

• [1] San Diego Natural History Museum "Fossil Mysteries Field Guide: Sespia californica