Jewish assimilation refers either to the gradual cultural assimilation and social integration of Jews in their surrounding culture or to an ideological program in the age of emancipation promoting conformity as a potential solution to historic Jewish marginalization.

The Holocaust was the genocide of European Jews during World War II. Between 1941 and 1945, Nazi Germany and its collaborators systematically murdered some six million Jews across German-occupied Europe, around two-thirds of Europe's Jewish population. The murders were carried out primarily through mass shootings and poison gas in extermination camps, chiefly Auschwitz-Birkenau, Treblinka, Belzec, Sobibor, and Chełmno in occupied Poland. Separate Nazi persecutions killed a similar or larger number of non-Jewish civilians and POWs; the term Holocaust is sometimes used to refer to the persecution of these other groups.