When the holotype was first described by Samuel Paul Welles in 1962,[1] it was described as Alzadasaurus colombiensis before being moved into its current genus by Kenneth Carpenter in 1999.

[2] Callawayasaurus is named in honor of the paleontologist Jack M. Callaway, editor of Ancient Marine Reptiles who, as Carpenter put it, "in his brief career as a vertebrate paleontologist, did much to improve our understanding of marine reptiles.

"[2] The familiar suffix, -saurus comes from the Greek sauros (σαυρος), meaning "lizard" or "reptile.

[3] The first Callawayasaurus remains were found in the Paja Formation near Leiva, Boyaca Colombia.

[3] Callawayasaurus are known from the Aptian faunal stage of the early Cretaceous period, which extended from 125 to 112 million years ago.