Although Jews, whom the Nazis deemed a priority danger to Germany, were the primary victims of Nazi racism, other victims included some 200,000 Gypsies. At least 200,000 mentally or physically disabled patients, mainly Germans, living in institutional settings, were murdered in the so-called Euthanasia Program.

As Nazi tyranny spread across Europe, the Germans and their collaborators persecuted and murdered millions of other people. Between two and three million Soviet prisoners of war were murdered or died of starvation, disease, neglect, or maltreatment. The Germans targeted the non-Jewish Polish intelligentsia for killing, and deported millions of Polish and Soviet civilians for forced labor in Germany or in occupied Poland, where these individuals worked and often died under deplorable conditions.

From the earliest years of the Nazi regime, German authorities persecuted homosexuals and others whose behavior did not match prescribed social norms. German police officials targeted thousands of political opponents (including Communists, Socialists, and trade unionists) and religious dissidents (such as Jehovah's Witnesses). Many of these individuals died as a result of incarceration and maltreatment.

Though the Nazis tried to keep operation of camps secret, the scale of the killing made this virtually impossible. Eyewitnesses brought reports of Nazi atrocities in Poland to the Allied governments, who were harshly criticized after the war for their failure to respond, or to publicize news of the mass slaughter. This lack of action was likely mostly due to the Allied focus on winning the war at hand, but was also a result of the general incomprehension with which news of the Holocaust was met and the denial and disbelief that such atrocities could be occurring on such a scale. At Auschwitz alone, more than 2 million people were murdered in a process resembling a large-scale industrial operation. A large population of Jewish and non-Jewish inmates worked in the labor camp there; though only Jews were gassed, thousands of others died of starvation or disease. During the summer of 1944, even as the events of D-Day (June 6, 1944) and a Soviet offensive the same month spelled the beginning of the end for Germany in the war, a large proportion of Hungary’s Jewish population was deported to Auschwitz, and as many as 12,000 Jews were killed every day.