Edaphosauridae is a family of mostly large (up to 3 m (9.8 ft) or more) Late Carboniferous to Early Permian synapsids.

Edaphosaur fossils are so far known only from North America and Europe.

[3] The head is small in relation to the bulky body, and there is a tall sail along the back, which may have functioned as a thermoregulatory device.

The interrelationships of Edaphosauridae was investigated in details by David M. Mazierski and Robert R. Reisz (2010).

Protorothyris archeri Ophiacodontidae Varanopidae Caseasauria Ianthodon schultzei Ianthasaurus hardestiorum Glaucosaurus megalops Lupeosaurus kayi Edaphosaurus boanerges Edaphosaurus novomexicanus Haptodus garnettensis Pantelosaurus saxonicus Therapsida Sphenacodontidae