The House of Borgia (/ˈbɔːr(d)ʒə/ BOR-zhə, BOR-jə; Italian: [ˈbɔrdʒa]; Spanish and Aragonese: Borja [ˈboɾxa]; Valencian: Borja [ˈbɔɾdʒa]) was a noble family of Spanish origins, which rose to prominence during the Italian Renaissance. They were from Xàtiva, Kingdom of Valencia, the surname being a toponymic from the town of Borja, then in the Crown of Aragon, in Spain.

The Borgias became prominent in ecclesiastical and political affairs in the 15th and 16th centuries, producing two popes: Alfons de Borja, who ruled as Pope Callixtus III during 1455–1458, and his nephew Rodrigo Lanzol Borgia, as Pope Alexander VI, during 1492–1503.

Especially during the reign of Alexander VI, they were suspected of many crimes, including adultery, incest, simony, theft, bribery, and murder (especially murder by arsenic poisoning). Because of their grasping for power, they made enemies of the Medici, the Sforza, and the Dominican friar Girolamo Savonarola, among others. They were also patrons of the arts who contributed to the development of Renaissance art.

The Borgia family stands out in history as being infamously steeped in sin and immorality, yet there is evidence to suggest that this one-dimensional characterization is a result of undeserved contemporary critiques.

The Borja was a noble house with origin in the town of Borja (Zaragoza) in the then Crown of Aragon. During this time, there were numerous unsubstantiated claims that the family was of originally Jewish descent, and were pretending to be pious Roman Catholics. These underground rumours were propagated by, among others, Giuliano della Rovere, and the family was frequently described as marranos by political opponents. The rumours have persisted in popular culture for centuries, listed in the Semi-Gotha of 1912. The family themselves propagated a spurious genealogical descent from a 12th-century claimant to the crown of the Kingdom of Aragon, Pedro de Atarés, Lord of Borja, who actually died childless.

Alfons de Borja (1378–1458) was born to Francina Llançol and Domingo de Borja in La Torreta, Canals, which was then situated in the Kingdom of Valencia.

Alfons de Borja was a professor of law at the University of Lleida, then a diplomat for the Kings of Aragon before becoming a cardinal. At an advanced age, he was elected Pope Callixtus III in 1455 as a compromise candidate and reigned as Pope for just three years, until his death in 1458.

Rodrigo Borgia (1431–1503) was born in Xàtiva, also in the Kingdom of Valencia, to Isabel de Borja i Cavanilles and Jofré Llançol i Escrivà. He studied law at Bologna and was appointed as cardinal by his uncle, Alfons Borgia, Pope Callixtus III. He was elected Pope in 1492, taking the regnal name Alexander VI. While a cardinal, he maintained a long-term illicit relationship with Vannozza dei Cattanei, with whom he had four children: Giovanni; Cesare; Lucrezia; and Gioffre. Rodrigo also had children by other women, including one daughter with his mistress, Giulia Farnese.