The Kuvasz is a breed of ancient origin, believed to be one of the oldest Molossers alive. There are various theories concerning the breed's origin and its name, from those suggesting that it is the Sumerian ancestor of the Tibetan Mastiff and that its original name was Ku Assa, meaning "Horse Dog" of the proto-Magyars, to those claiming that it's descended from the Akbash brought to Hungary by the Turks, whose great white dogs came into contact with other Molossers and Wolfhounds of the region and that its name is a corruption of the name Kawaz, meaning "Guard of Nobility" and so on. These theories have been around for many years and while they seem to touch upon some "accidental truths", there isn't much historical evidence to back them up. Many facts are being ignored, such as the existence of white guard dogs in Hungary before the Ottoman invasion, or the impossibility of the supposed Sumerian and Magyar connection because of basic chronology and other faults.

A theory which seems to be the most likely one suggests that the original white guard dogs associated with the region were descended from the prized watchdogs of the old Russian Chuvash group of farmers, hunters and herdsmen, which employed working crosses of dogs from the Carpathian mountains, namely old Hutsul Wolfdogs and their Borzoi-like hounds to protect their livestock and hunt large game. Bred for colour, temperament and agility, the original variety of the Kuvasz was already its own breed long before the Turkish invasion. During the 2nd part of the 15th century, these impressive white dogs were kept by the Hungarian King Matyas, who bred his own strain and used them as personal bodyguards, while the rest of the nobility employed them as hunters and watchdogs.