The history of the Jews in Italy spans more than two thousand years to the present. The Jewish presence in Italy dates to the pre-Christian Roman period and has continued, despite periods of extreme persecution and expulsions, until the present. As of 2019, the estimated core Jewish population in Italy numbers around 45,000.As reported by the American Jewish Yearbook (2007), on a total Italian population of circa 60 million people, which therefore is approx. 0.075%. Greater concentrations are in Rome and Milan. Cf. the demographic statistics by Sergio DellaPergola, published on World Jewish Population , American Jewish Committee, 2007.URL accessed 13 March 2013. As data originate from records kept by the various Italian Jewish congregations (which means they register "observant" Jews who have somehow had to go through basic rituals such as the Brit Milah or Bar/Bat Mitzvah etc.). Excluded are therefore "ethnic Jews", lay Jews, atheist/agnostic Jews, et al. – cfr. "Who is a Jew?". If these are added, then the total population would increase, possibly to approx. 45,000 Jews in Italy, not counting recent migrations from North Africa and Eastern Europe. In 2023, the Center for Studies of New Religions estimated the total at 36,000 while the Union of Italian Jewish Communities put the number at 27,000.

Early Jewish presence

The Jewish community in Rome is likely one of the oldest continuous Jewish communities in the world, existing from classical times until today. Most certainly, it is known that in 139 BCE, Simon Maccabeus sent a Hasmonean embassy to Rome in order to strengthen his alliance with the Roman Republic against the Hellenistic Seleucid kingdom.1 Maccabees 14: 24: "After this Simon sent Numenius to Rome with a large gold shield weighing a thousand minas, to confirm the alliance with the Romans." The ambassadors received a cordial welcome from their coreligionists already established in Rome.

Large numbers of Jews even lived in Rome during the late Roman Republican period (from around 150 BCE). They were largely Greek-speaking and poor. As Rome had increasing contact with and military/trade dealings with the Greek-speaking Levant, during the 2nd and 1st centuries BCE, many Greeks, as well as Jews, came to Rome as merchants or were brought there as slaves.Philo of Alexandria, with Charles Duke Yonge, trans., The works of Philo Judaeus, the contemporary of Josephus (London, England: Henry G. Bohn, 1855), vol. 4, "A treatise on the virtues and on the office of ambassadors. Addressed to Caius.", p. 134. From p. 134: "How then did he [i.e., the emperor Caligula] look upon the great division of Rome which is on the other side of the river Tiber, which he was well aware was occupied and inhabited by the Jews? And they were mostly Roman citizens, having been emancipated; for, having been brought as captives into Italy, they were manumitted by those who had bought them for slaves, without ever having been compelled to alter any of their heredity or national observances." In Aquileia, a first century BC inscription mentions a freedman named Lucius Aiacius Dama, possibly originating from Damascus, who describes himself as a "Iudaeus", a Jew. The Lucilii Gamalae, a prominent Ostian family, have been suggested to descend from a slave from Gamla who took the cognomen Gamala from his city of origin, perhaps arriving in Italy as early as Pompey's conquest of Judaea in 63 BCE.

The Romans appear to have viewed the Jews as followers of peculiar, backward religious customs, but antisemitism as it would come to be in the Christian and Islamic worlds did not exist (see Anti-Judaism in the pre-Christian Roman Empire).However, the Roman author Valerius Maximus in Book 1, Chapter 3, § 3 of his book Factorum ac dictorum memorabilium libri IX (Nine books of memorable deeds and sayings), states that during the consulship of Marcus Popillius Laenas and Gnaeus Calpurnius (c. 139 BC), the praetor Gnaeus Cornelius Hispanus expelled the Jews from Rome because they had tried to spread their religion among the Romans. See: Valerius Maximus, with Carl Halm, ed., Factorum et dictorum memorabilium libri novem (Leipzig, (Germany): Teubner, 1865), p. 17. (in Latin) Valerius Maximus with Henry John Walker, trans., Memorable Deeds and Sayings: One Thousand Tales from Ancient Rome (Indianapolis, Indiana, U.S.: Hackett Publishing Co., 2004), p. 14. Despite their disdain, the Romans did recognize and respect the antiquity of the Jews' religion and the fame of their Temple in Jerusalem (Herod's Temple). Many Romans did not know much about Judaism, including the emperor Augustus who, according to his biographer Suetonius, thought that Jews fasted on the sabbath. Julius Caesar was known as a great friend to the Jews, and they were among the first to mourn his assassination.https://www.jewishvirtuallibrary.org/jsource/judaica/ejud_0002_0011_0_10485.html; Suetonius, Divus Iulius, 84 (http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Suetonius/12Caesars/Julius*.html#34)

In Rome, the community was highly organized, and presided over by heads called άρχοντες (archontes) or γερουσιάρχοι (gerousiarchoi). The Jews maintained in Rome several synagogues, whose spiritual leader was called αρχισυνάγωγος (archisynagogos). Their tombstones, mostly in Greek with a few in Hebrew/Aramaic or Latin, were decorated with the ritual menorah (seven-branched candelabrum).

Some scholars have previously argued that Jews in the pre-Christian Roman Empire were active in proselytising Romans in Judaism, leading to an increasing number of outright converts.McGing, Brian: Population and proselytism: how many Jews were there in the ancient world?., in Bartlett, John R. (ed.): Jews in the Hellenistic and Roman Cities. Routledge, 2002. The new consensus is, that this is not the case.Gregerman, A. (2011): The Lack of Evidence for a Jewish Christian Countermission in Galatia. Studies in Christian-Jewish Relations, 4 (1). According to Erich S. Gruen, though conversions did happen, there is no evidence of Jews trying to convert Gentiles to Judaism.Gruen, Erich S.: Diaspora: Jews amidst Greeks and Romans, p. 46. Harvard University Press, 2004. Leonard V. Rutgers has shown, on the basis of tomb counts in the Jewish Vigna Randanini and Villa Torlonia catacombs, that the Jewish community in third- and fourth-century Rome made up about one to two percent of the city’s population. It has also been argued that some people adopted some Jewish practices and belief in the Jewish God without actually converting (called God-fearers).

The fate of Jews in Rome and Italy fluctuated, with partial expulsions being carried out under the emperors Tiberius and Claudius.The expulsion of the Jews from Rome by the emperor Tiberius is mentioned in: Josephus Flavius, with William Whiston, trans., The Genuine Works of Flavius Josephus (New York, New York: Robinson, Pratt & Co., 1841), vol. 4, The Antiquities of the Jews: Book 18, Chapter 3, § 5, p. 68. From p. 68: "There was a man who was a Jew, but had been driven away from his own country by an accusation laid against him for transgressing their laws, and by the fear he was under of punishment for the same; but in all respects a wicked man. He, then living at Rome, professed to instruct men in the wisdom of the laws of Moses. He procured also three other men, entirely of the same character with himself, to be his partners. These men persuaded Fulvia, a woman of great dignity, and one that had embraced the Jewish religion, to send purple and gold to the temple at Jerusalem; and when they had gotten them, they employed them for their own uses, and spent the money themselves, on which account it was that they at first required it of her. Whereupon Tiberius, who had been informed of the thing by Saturninus, the husband of Fulvia, who desired inquiry might be made about it, ordered all of the Jews to be banished out of Rome; at which time the consuls listed four thousand men out of them, and sent them to the island of Sardinia; but punished a greater number of them, who were unwilling to become soldiers, on account of keeping the laws of their forefathers. Thus were the Jews banished out of the city by the wickedness of four men." Cornelius Tacitus, The Annals (Philadelphia, Pennsylvania, U.S.: David McKay, 1897), Book 2, § 85, pp. 122–123. From pp. 122–123: "Measures were also taken for exterminating the solemnities of the Jews and the Egyptians; and a decree of the senate was passed, that four thousand descendants of franchised slaves, defiled with that superstition, and of age to carry arms, should be deported to Sardinia, to check the practice of freebootery there; and if, through the malignity of the climate, they perished, it would be small loss; that the rest should depart Italy, unless by a stated day they had renounced their profane rites." Suetonius, The Lives of the Twelve Caesars (New York, New York: The Modern Library, 1931), § 36, p. 142. From p. 142: "He [i.e., the emperor Tiberius] abolished foreign cults, especially the Egyptian and the Jewish rites, compelling all who were addicted to such superstitions to burn their religious vestments and all their paraphernalia. Those of the Jews who were of military age he assigned to provinces of less healthy climate, ostensibly to serve in the army. Others of the same race or of similar beliefs he banished from the city, on pain of slavery for life if they did not obey." Cassius Dio with Earnest Cary, trans., Dio's Roman History (London, England: William Heinemann Ltd., 1968), vol. 7, Book 57, Ch. 18, line 5a, p. 163. From p. 163: "As the Jews had flocked to Rome in great numbers and were converting many of the natives to their ways, he [i.e., the emperor Tiberius] banished most of them." The expulsion of the Jews from Rome by the emperor Claudius is mentioned in: Acts 18:1–3: "After this, Paul left Athens and went to Corinth. There he met a Jew named Aquila, a native of Pontus, who had recently come from Italy with his wife Priscilla, because Claudius had ordered all Jews to leave Rome. Paul went to see them, and because he was a tentmaker as they were, he stayed and worked with them." Suetonius, The Lives of the Twelve Caesars (New York, New York: The Modern Library, 1931), §25, p. 227. From p. 227: "Since the Jews constantly made disturbances at the instigation of Chrestus, he [i.e., the emperor Claudius] expelled them from Rome." However, Cassius Dio states that Claudius did not expel all of the Jews from Rome. Cassius Dio with Earnest Cary, trans., Dio's Roman History (London, England: William Heinemann Ltd., 1968), vol. 7, Book 60, Ch. 6, lines 6–7, p. 383. From p. 383: "As for the Jews, who had again increased so greatly that by reason of their multitude it would have been hard without raising a tumult to bar them from the city, he did not drive them out, but ordered them, while continuing their traditional mode of life, not to hold meetings." See also Wikipedia's article: Claudius' expulsion of Jews from Rome.

Following the Jewish–Roman Wars After the First Jewish Revolt (66–73/74 CE) and the Bar Kokhba Revolt (132–136 CE), large numbers of Jews were brought from Judaea to Italy as slaves, in keeping with common Roman practice of enslaving prisoners of war and populations of defeated peoples. As a result, most of the Jewish population in Italy in the following period is thought to have originated from these captives.