Numerous are the theses respect to the etymology of the name, at first Ioe, Yoy, Yoyo, Iohe, Ioha, Joio and it finally Gioi. For many people it represents the qualities of the citizens and the prerogatives that distinguish them, according to others the name derives from the existence of a pagan temple devoted to Jupiter, now situated where the church of St. Eustachio rises.It must count its fortunes to the unusual geographical position, on whose the Enotris raised one of their fortitudes shelter that went to belong to the «Chora» of Velia.

The first news goes up again to 1034 and we believe that the actual inhabited center has had origin around to a fortitude of the VII century.Many believe that the country was in origin situated in the place «Sterza» ; others believe that this last was its necropolis. Gioi has been built before the year 1000 and is supposed that has reached a notable increase when, with the destruction of Elea (Velia), in the VI century of the Christian era, the survivors looked for shelter in the hinterland.

The village suffered the lucan and roman domination, and also the colonization of the longobardi, as his ex hamlets of Sala and Salella testify, belonging to the agricultural system of the «Curtis. » Its prestige increased in Norman age, when it became after Monteforte and Magliano, the third defensive rampart of the Fortress of Novi and was famous the university of Gioi that made part of the Barony of Novi.

In the middle age around the village was built surrounded walls rich of circular and quadrangular towers, still visible in more points, culminated with a castle. The entry to the country was allowed by seven doors of which only a still existing (PORTANOVA).

This door, denominated today Door Of the Leos, has to the base two stretched out lions on which two tall grooved pillars of compact stone are raised, originally surmounted by a lintel. The ancient castle, on whose ruins are drawn a public garden, is the tallest point of the country and from here it is possible to admire a stupendous panorama. In 1498 it became feud of Berengario Carafa to pass in dowry to the family Pignatelli. The ancient state of Gioi, constituted in 1515, included the hamlets of Ostigliano, Perito, Oria, Piano Vetrale, Sala, Salella, Cardile, Moio and Pellare.

The population, in the year 1532, counted 1446 inhabitants. Giustiniani puts in evidence the rich trafficis operated by the gioiesis in the sector of the agricultural products, the small specialized family industries in the workmanship of the wool cloths and the leathers, as also in the breeding of the silkworm. The history of Gioi narrates then, that the country escaped to the tied up destruction to the war of the Evening subsequently passing under the Aragonese dominion. In the XIII century, the plague struck a first time the village and it reduced the population of it from 15000 inhabitants to as soon as 3000.

In 1614 Giacomo Zattera sold it to the Genoese. The '600 were one century of great commerce of feuds and also Gioi passed before to Pasca family and then to Don Joseph Galeota. In 1645 an epidemic of «sore throat» raged on it and in little days it depopulated entirely almost the city. After the plague a lot of families emigrated and became the slow decadence of Gioi. In 1659 it passed to the regal «demanio» to be registered then to the Pasca when the Barony of Novi was dismembered. At the end of the '700 Gioi results in possession of the family Ciardulli.