Kayoceras is a genus of middle Silurian nautiloid cephalopods, known from Iowa and Illinois, belonging to the Discosoridae.

Related genera include Discosorus, Endodiscosorus, and Stokesoceras.

Kayoceras has a short, breviconic shell, like Discosorus, but with a more central siphuncle.

Derivation is probably from Discosorus, through an evolutionary shifting of the siphuncle position, which has its origin in the Lowoceratidae, possibly through Tuyloceras.

This prehistoric nautiloid-related article is a stub.