Ashkenazi (plural: Ashkenazim) refers to Jews whose ancestry traces to the medieval Jewish communities of the Rhine Valley and northern France, who later migrated eastward into Central and Eastern Europe. The term derives from Ashkenaz, the Hebrew name for the Germanic lands. Ashkenazim are the largest Jewish ethnic division in the modern world, comprising the majority of Jewish populations in the United States, Western Europe, and Israel, and making up an estimated 70-80% of world Jewry prior to the Holocaust.¹⁾ They are distinguished from Sephardim (Jews of Iberian origin), Mizrahim (Jews of Middle Eastern and North African origin), and other Jewish ethnic communities by distinct liturgical traditions, the historical use of Yiddish as a vernacular language, and a well-documented set of shared genetic markers.

The medieval Ashkenazi communities - known as the Kehillot of the Rhineland - developed distinctive religious and legal traditions, particularly around the rulings of Rabbi Gershom ben Judah (c. 960-1040 CE) and later Rashi (1040-1105 CE). Persecution, including the massacres of the First Crusade (1096 CE), drove substantial eastward migration into Poland, Lithuania, and the broader Polish-Lithuanian Commonwealth, where Ashkenazi communities flourished for several centuries. By the early modern period, Eastern Europe hosted the largest concentrated Jewish population in the world. The Holocaust (1941-1945) killed an estimated six million Jews, the majority of them Ashkenazim, devastating these communities. For a fuller treatment of this history, see Ashkenazi - History.

Population genetics has established that Ashkenazi Jews form a genetically distinct group with characteristics consistent with a founder effect - a period of reduced population size followed by expansion - estimated to have occurred roughly 600-800 years ago from a founding population of perhaps 300-400 individuals. Studies identify a combination of Levantine (Middle Eastern) and Southern European ancestry, consistent with an ancient origin in the Levant and admixture during residence in the Mediterranean before northward migration. Ashkenazi Jews carry elevated frequencies of several genetic variants associated with specific diseases, including Tay-Sachs, Gaucher disease, BRCA1/2 mutations, and others, which population geneticists attribute to the founder effect and subsequent endogamy.

The degree to which Ashkenazi ancestry is primarily Levantine versus European, and the relative contribution of male versus female lineages, remains an area of active scholarly discussion. See Ashkenazi - Genetics Consensus and Khazar Hypothesis for competing interpretations.

Contemporary estimates place the global Ashkenazi population at approximately 10-11 million, though definitions and counting methods vary. The United States has the largest Ashkenazi population outside Israel, with major concentrations in the New York metropolitan area, Los Angeles, Chicago, and other urban centers. Israel's Ashkenazi population constitutes a plurality of Israeli Jews, though Mizrahi and Sephardi Jews combined now represent a majority.²⁾ Ashkenazim have been demographically and culturally prominent in European and American Jewish institutional life, academia, arts, and commerce, a prominence that has generated both sociological analysis and, in some quarters, antisemitic conspiracy theories.

A body of psychometric and sociological research has examined the relatively high mean IQ scores and disproportionate representation of Ashkenazi Jews in intellectual and professional fields. Some researchers, including Gregory Cochran, Henry Harpending, and Jason Hardy, have proposed evolutionary hypotheses linking Ashkenazi cognitive profiles to historical occupational selection pressures during the medieval period. This research is contested on methodological, historical, and interpretive grounds. See Ashkenazi Intelligence - Viewpoint for the range of positions.

The mainstream consensus in population genetics holds that Ashkenazi Jews descend primarily from a Jewish population of ancient Levantine origin, with significant Southern European admixture, and that the Khazar Hypothesis - which proposes a primary origin among the Turkic Khazar people of the Caucasus - is not supported by current genetic evidence. See Ashkenazi - Genetics Consensus. The intelligence research does not have equivalent consensus standing and remains disputed in methodology and interpretation.

• Khazar Hypothesis - The position that Ashkenazi Jews descend primarily or substantially from the Khazar Khaganate, a Turkic polity whose ruling class reportedly converted to Judaism in the 8th-9th centuries CE.
• Ashkenazi Intelligence - Viewpoint - Competing interpretations of psychometric data, evolutionary hypotheses, and sociological explanations for observed patterns of Ashkenazi achievement.
• Ashkenazi Identity - Viewpoint - Debates over whether Ashkenazi Jews constitute an ethnic group, a religious community, a nation, or some combination, and how these definitions interact with Israeli law and diaspora politics.

• Ashkenazi - History
• Ashkenazi - Genetics Consensus
• Khazar Hypothesis
• Yiddish
• Sephardi
• Mizrahi
• Jewish Diaspora
• Holocaust

1. Behar, D.M., et al. (2010). “The genome-wide structure of the Jewish people.” Nature, 466, 238-242.
2. Moorjani, P., et al. (2011). “The history of African gene flow into Southern Europeans, Levantines, and Jews.” PLOS Genetics, 7(4).
3. Cochran, G., Hardy, J., & Harpending, H. (2006). “Natural history of Ashkenazi intelligence.” Journal of Biosocial Science, 38(5), 659-693.
4. DellaPergola, S. (2015). “World Jewish Population, 2015.” American Jewish Year Book, 115, 273-364.
5. Stampfer, S. (2013). “Did the Khazars Convert to Judaism?” Jewish Social Studies, 19(3), 1-72.
6. Seltzer, R.M. (1980). Jewish People, Jewish Thought. Macmillan.