Gianantonio Davia (13 October 1660 – 11 January 1740) was an Italian Roman Catholic cardinal.
He was born in Bologna to a prominent family, whose name is also spelled as D'Avia and De Via. He was educated in both canon and civil law at the University of Bologna, and early in life, served as a magistrate and a soldier in the war between Venice and the Ottomans in 1684, where he took part in the siege of Santa Maura. He then moved to Rome, where he rose rapidly in the ecclesiastical ranks, despite never attending seminary. He served as nuncio in Cologne, Poland, and ultimately Austria by 1700, only to be expelled from Vienna after the death of Emperor Leopold I by his successor, Emperor Joseph I, in May 1706. On May 18, 1712; he was named a cardinal. He participated in the conclaves of 1721, 1724, and 1730.
In 1727, he was named Protector of Scotland, and minister of England to the exiled of Stuart pretender in Rome in April 1728. He was accused of supporting Jansenism on several occasions. He died in Rome and was buried at San Lorenzo in Lucina.