Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute, discoidal shells. Hyatt and Smith (1905, p. 114-115) included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the more advanced Gymnites. Those being Xenaspis, Flemingites, and Ophiceras. Derivation as shown in Smith (1932 p. 30) is from Xenodiscus.