Sephardi Jews, Mizrahi Jews, and other Jewish ethnic divisions.

Ashkenazi Jews, also known as Ashkenazic Jews or Ashkenazim (Hebrew: אַשְׁכֲּנָזִים‎, pronounced [ˌaʃkəˈnazim], singular: [ˌaʃkəˈnazi]; also יְהוּדֵי אַשְׁכֲּנָז, Yehudei Ashkenaz, "the Jews of Ashkenaz"), are the Jews descended from the medieval Jewish communities along the Rhine in Germany from Alsace in the south to the Rhineland in the north. Ashkenaz is the medieval Hebrew name for this region and thus for Germany. Thus, Ashkenazim or Ashkenazi Jews are literally "German Jews." Later, Jews from Western and Central Europe came to be called "Ashkenaz" because the main centers of Jewish learning were located in Germany. (See Usage of the name for the term's etymology.) Ashkenaz is also a Japhetic patriarch in the Table of Nations (Genesis 10).

Many Ashkenazi Jews later migrated, largely eastward, forming communities in non German-speaking areas, including Hungary, Poland, Lithuania, Russia, Ukraine, Eastern Europe, and elsewhere between the 11th and 19th centuries. With them, they took and diversified Yiddish, a basically Germanic language with Hebrew influence (see Jewish language). It had developed in medieval times as the lingua franca among Ashkenazi Jews. The Jewish communities of three cities along the Rhine, Speyer, Worms and Mainz created the SHUM league (SHUM after the first Hebrew letters of Spira, Warmatia and Magentza). The SHUM-cities are considered the cradle of the distinct Ashkenazi culture and liturgy.

Although in the 11th century they comprised only 3 percent of the world's Jewish population, Ashkenazi Jews accounted for (at their peak) 92 percent of the world's Jews in 1931 and today make up approximately 80 percent of Jews worldwide. Most Jewish communities with extended histories in Europe are Ashkenazim, with the exception of those associated with the Mediterranean region. The majority of the Jews who migrated from Europe to other continents in the past two centuries are Ashkenazim, Eastern Ashkenazim in particular. This is especially true in the United States, where most of the 5.3 million American Jewish population is Ashkenazi, representing the world's single largest concentration of Ashkenazim.