Nazi analogies or Nazi comparisons are any comparisons or parallels which are related to Nazism or Nazi Germany, which often reference Adolf Hitler, Joseph Goebbels, the SS, or the Holocaust. Despite criticism, such comparisons have been employed for a wide variety of reasons since Hitler's rise to power. Some Nazi comparisons are logical fallacies, such as reductio ad Hitlerum. Godwin's law asserts that a Nazi analogy is increasingly likely the longer an internet discussion continues; Mike Godwin also stated that not all Nazi comparisons are invalid.

Reductio ad Hitlerum, also known as playing the Nazi card, is an attempt to invalidate someone else's argument on the basis that the same idea was promoted or practised by Adolf Hitler or the Nazi Party. Arguments can be termed reductio ad Hitlerum if they are fallacious. Contrarily, straightforward arguments critiquing specifically fascist components of Nazism like Führerprinzip are not part of the association fallacy.