The Jewish diaspora (Hebrew: גוֹלָה gōlā), alternatively the dispersion (תְּפוּצָה təfūṣā) or the exile (גָּלוּת gālūṯ; Yiddish: גלות gōləs), consists of Jews who reside outside of the Land of Israel. Historically, it refers to the expansive scattering of the Israelites out of their homeland in the Southern Levant and their subsequent settlement in other parts of the world, which gave rise to the various Jewish communities.

In the Hebrew Bible, the term gālūṯ (lit. 'exile') denotes the fate of the Twelve Tribes of Israel over the course of two major exilic events in ancient Israel and Judah: the Assyrian captivity, which occurred after the Kingdom of Israel was conquered by the Neo-Assyrian Empire in the 8th century BCE; and the Babylonian captivity, which occurred after the Kingdom of Judah was conquered by the Neo-Babylonian Empire in the 6th century BCE. While those who were taken from Israel dispersed as the Ten Lost Tribes, those who were taken from Judah—consisting of the Tribe of Judah and the Tribe of Benjamin—became known by the identity "Jew" (יְהוּדִי Yehūdī, lit. 'of Judah') and were repatriated following the Persian conquest of Babylonia.

A Jewish diaspora population existed for many centuries before the Roman siege of Jerusalem in 70 CE. In the preceding Second Temple period, it existed as a consequence of various factors, including the creation of political and war refugees, enslavement, deportation, overpopulation, indebtedness, military employment, and opportunities in business, commerce, and agriculture. Prior to the mid-1st century CE, in addition to Judea, Syria, and Babylonia, large Jewish communities existed in the Roman provinces of Egypt, Crete and Cyrenaica, and in Rome itself. In 6 CE, most of the Southern Levant was organized as the Roman province of Judaea, where a large uprising led to the First Jewish–Roman War, which destroyed the Second Temple and most of Jerusalem. The Jewish defeat to the Roman army and the accompanying elimination of the symbolic centre of Jewish identity (the Temple in Jerusalem) marked the end of Second Temple Judaism, motivating many Jews to formulate a new self-definition and adjust their existence to the prospect of an indefinite period of displacement. Nevertheless, intermittent warfare between Jewish nationalists and the Roman Empire continued for several decades. In 129/130 CE, the Roman emperor Hadrian ordered the construction of Aelia Capitolina over the ruins of Jerusalem, sparking the Bar Kokhba revolt in 132 CE. Led by Simon bar Kokhba, this uprising endured for four years, but was ultimately unsuccessful and became the last of the Jewish–Roman wars; Jews were massacred or displaced across the province, banned from Jerusalem and its surrounding areas, and forbidden to practice Judaism, leading to a significant rise in the Jewish diaspora.

By the Middle Ages, owing to increasing migration and resettlement, diaspora Jews divided into distinct regional groups that are generally addressed according to two primary geographical groupings: the Ashkenazi Jews, who coalesced in the Holy Roman Empire and Eastern Europe; and the Sephardic Jews, who coalesced in the Iberian Peninsula and the Arab world. These groups have parallel histories, sharing many cultural similarities and experiences of persecution and expulsions and exoduses, such as the expulsion from England in 1290, the expulsion from Spain in 1492, and the expulsion from the Muslim world after 1948. Although the two branches comprise many unique ethno-cultural practices and have links to their local host populations (such as Central Europeans for Ashkenazi Jews, and Hispanics and Arabs for Sephardic Jews), their common religious practices and shared ancestry, as well as their continuous communication and population transfers, have been responsible for cementing a unified sense of peoplehood between them since the late Roman period.

Diaspora has been a common phenomenon for many peoples since antiquity, but what is particular about the Jewish instance is the pronounced negative, religious, indeed metaphysical connotations traditionally attached to dispersion and exile (galut), two conditions which were conflated. The English term diaspora, which entered usage as late as 1876, and the Hebrew word galut though covering a similar semantic range, bear some distinct differences in connotation. The former has no traditional equivalent in Hebrew usage.

Steven Bowman argues that diaspora in antiquity connoted emigration from an ancestral mother city, with the emigrant community maintaining its cultural ties with the place of origin. Just as the Greek city exported its surplus population, so did Jerusalem, while remaining the cultural and religious centre or metropolis (ir-va-em be-yisrael) for the outlying communities. It could have two senses in Biblical terms, the idea of becoming a 'guiding light unto the nations' by dwelling in the midst of gentiles, or of enduring the pain of exile from one's homeland. The conditions of diaspora in the former case were premised on the free exercise of citizenship or resident alien status. Galut implies by comparison living as a denigrated minority, stripped of such rights, in the host society. Sometimes diaspora and galut are defined as 'voluntary' as opposed to 'involuntary' exile. Diaspora, it has been argued, has a political edge, referring to geopolitical dispersion, which may be involuntary, but which can assume, under different conditions, a positive nuance. Galut is more teleological, and connotes a sense of uprootedness. Daniel Boyarin defines diaspora as a state where people have a dual cultural allegiance, productive of a double consciousness, and in this sense a cultural condition not premised on any particular history, as opposed to galut, which is more descriptive of an existential situation, that properly of exile, conveying a particular psychological outlook.

The Greek word διασπορά (dispersion) first appears as a neologism in the translation of the Old Testament known as the Septuagint, where it occurs 14 times, starting with a passage reading: ἔση διασπορὰ ἐν πάσαις βασιλείαις τῆς γῆς ('thou shalt be a diaspora (or dispersion) in all kingdoms of the earth', Deuteronomy 28:25), translating 'ləza'ăwāh', whose root suggests 'trouble, terror'. In these contexts it never translated any term in the original Tanakh drawn from the Hebrew root glt (גלה), which lies behind galah, and golah, nor even galuth. Golah appears 42 times, and galuth in 15 passages, and first occurs in the 2 Kings 17:23's reference to the deportation of the Judean elite to Babylonia. Stéphane Dufoix, in surveying the textual evidence, draws the following conclusion:

galuth and diaspora are drawn from two completely different lexicons. The first refers to episodes, precise and datable, in the history of the people of Israel, when the latter was subjected to a foreign occupation, such as that of Babylon, in which most of the occurrences are found. The second, perhaps with a single exception that remains debatable, is never used to speak of the past and does not concern Babylon; the instrument of dispersion is never the historical sovereign of another country. Diaspora is the word for chastisement, but the dispersion in question has not occurred yet: it is potential, conditional on the Jews not respecting the law of God. . . It follows that diaspora belongs, not to the domain of history, but of theology.'