Counter-Earth is a term used within the Gorean novels for the world of Gor, described as a planet placed on the opposite side of the Sun from Earth and therefore hidden from terrestrial observation. The device is a literary conceit that permits the author to imagine a parallel human society with different customs and structures.

The Counter-Earth motif has classical antecedents in ancient Greek natural philosophy, where the notion of a hypothetical planet occupying such a position was proposed and later discarded. Norman adopts the name and repurposes it for fiction.