Pseudolithos is a genus of succulent flowering plants of the family Apocynaceae, indigenous to arid areas of Somalia, Yemen and Oman.

The plants were first described as a genus in 1965; the name "Pseudo-lithos" means "false-stone" and refers to their pebble-like appearance.

[1] All species in this genus are highly succulent, small in size, and exhibit tessellation on their stems' surface.

[2][3] Phylogenetic studies have shown the genus to be monophyletic, and most closely related to the widespread Caralluma stapeliads of North Africa.

Marginally more distantly related is a sister branch comprising the genera Echidnopsis and Rhytidocaulon.