The master race (German: Herrenrasse [ˈhɛʁənˌʁasə]) is a pseudoscientific concept in Nazi ideology, in which the putative Aryan race is deemed the pinnacle of human racial hierarchy. Members were referred to as master humans (Herrenmenschen [ˈhɛʁənˌmɛnʃn̩]).

The Nazi theorist Alfred Rosenberg believed that the "Nordic race" was descended from Proto-Indo-Europeans, who he thought had pre-historically dwelt on the North German Plain and may have ultimately originated on the lost island of Atlantis. The Nazis declared that the Aryans were superior to all other races, and believed they were entitled to expand territorially. The actual policy that was implemented by the Nazis resulted in the Aryan certificate. This document, which was required by law for all citizens of the Reich, was the "Lesser Aryan certificate" (Kleiner Ariernachweis) and could be obtained through an Ahnenpass, which required the owner to trace their lineage through baptism, birth certificates, or certified proof thereof that all grandparents were of "Aryan descent".

The Slavs, Roma, and Jews were defined as being racially inferior and non-Aryan "Untermenschen", and were thus considered a danger to the Aryan or Germanic master race. According to the Nazi secret Hunger Plan and Generalplan Ost, the Slavic population was to be removed from Central Europe through expulsion, enslavement, starvation, and extermination, except for a small percentage who were deemed to be non-Slavic descendants of Germanic settlers, and thus suitable for Germanisation.

The 18th century saw the first scientific attempts to establish a racial divide between "masters" and "slaves", or the belief that a nation's ruling class is biologically superior to its ruled subjects. In his book History of the Ancient Government of France, published posthumously in 1727, Henri de Boulainvilliers attempted to prove that in France, the nobility represented the descendants of the old Frankish ruling class. In contrast, the majority of the population descended from the subject Gauls. As a result, two qualitatively different races faced off, and the only way to abolish the Franks' superiority was to destroy their civilization. Classical liberal theorists such as Volney and Sieyès refuted this theory by demonstrating that the French nobility was primarily composed of nouveaux riches from all over the country. Thus, the concept of a racially pure Frankish lineage was false.

In 1855, French count Arthur de Gobineau published his infamous work An Essay on the Inequality of the Human Races. Expanding upon Boulainvilliers' use of ethnography to defend the Ancien Régime against the Third Estate's claims, Gobineau divides the human species into three major groups: white, yellow and black, claiming that "history springs only from contact with the white races". He considers the Aryan race to be the pinnacle of human development, serving as the basis of all European aristocracies. However, inevitable miscegenation led to the "downfall of civilizations".

Gobineau's influence was minimal at first. In his letters to Alexis de Tocqueville, he complained that his book was getting little attention in France and was only having an impact in the United States. Despite his friendship with Gobineau Tocqueville who rejected the book, explaining that it was in accordance with the interests of slave owners in the Southern states. However, in the 1880s, the book gained popularity in Germany thanks to Cosima Wagner's efforts. In 1899, Houston Stewart Chamberlain, a Germanophile Englishman and Cosima Wagner's son-in-law, published The Foundations of the Nineteenth Century. Expanding on Gobineau's earlier theories, he argued that the Teutonic peoples had a profound influence on Western civilization. Chamberlain classified all European peoples, including Germans, Celts, Slavs, Greeks, and Latins, as the "Aryan race", which was built on ancient Proto-Indo-European culture. He saw the Nordic or Teutonic peoples as the leaders of the Aryan race, and essentially all races.

The German philosopher Friedrich Nietzsche introduced the concept of Übermensch, which translates to "Overman" or "Superman". In his 1883 book Also Sprach Zarathustra: Ein Buch für Alle und Keinen (Thus Spoke Zarathustra: A Book for All and None), he proposed the idea of the Übermensch as a goal for humanity. However, Nietzsche never developed the concept based on race. Instead, the Übermensch "seems to be the ideal aim of spiritual development more than a biological goal". Nazism distorted the concept's real meaning to suit its "master race" ideology.

By the late nineteenth and early twentieth centuries, it was believed that Indo-Europeans (generally referred to as Aryans) were the highest branch of humanity due to their technological advancement. This reasoning was simultaneously linked with Nordicism, which claimed that the "Nordic race" was the "purest" form of the Aryan race. Today, this view is regarded as a form of scientific racism. It contradicts the belief in racial equality by advocating the view that one race is superior to all other races.