In 1993 Jean-Jacques Lepage on the Normandy coast at the Cap de la Hève, near Ecqueville, Octeville-sur-Mer, Seine-Maritime, Haute-Normandie, found a ten centimetres long fossil of a petrosaur in a marine claystone layer. In 1998 Eric Buffetaut e.a. named a separate genus for it. The type species is Normannognathus wellnhoferi. The genus name is derived from Normannia, the Mediaeval Latin name for Normandy, and Greek gnathos, "jaw". The specific name honours Peter Wellnhofer.