Holocaust denial is an antisemitic conspiracy theory that asserts that the Nazi genocide of Jews, known as the Holocaust, is a myth, fabrication, or exaggeration. Holocaust denial involves making one or more of the following false statements:

• Nazi Germany's "Final Solution" was aimed only at deporting Jews from the territory of the Third Reich and did not include their extermination.
• Nazi authorities did not use extermination camps and gas chambers for the mass murder of Jews.
• The actual number of Jews murdered is significantly lower than the accepted figure of approximately 6 million.
• The Holocaust is a hoax perpetrated by the Allies, Jews, and/or the Soviet Union.

The methodologies of Holocaust deniers are based on a predetermined conclusion that ignores overwhelming historical evidence to the contrary. Scholars use the term denial to describe the views and methodology of Holocaust deniers in order to distinguish them from legitimate historical revisionists, who challenge orthodox interpretations of history using established historical methodologies. Holocaust deniers generally do not accept denial as an appropriate description of their activities and use the euphemism revisionism instead. In some former Eastern Bloc countries, Holocaust deniers do not deny the mass murder of Jews but deny the participation of their own nationals in the Holocaust.

Holocaust denial is considered a serious societal problem in many places where it occurs, and it is illegal in Israel and many European countries.