The Illuminati is a name given to several groups, both real and fictitious. Historically, the name usually refers to the Bavarian Illuminati, an Enlightenment-era secret society founded on 1 May 1776 in Bavaria, today part of Germany. The societys stated goals were to oppose superstition, obscurantism, religious influence over public life, and abuses of state power. The Illuminati did plenty of unusual things, such as using symbols like the owl, adopting pseudonyms to avoid identification, and having complicated hierarchies like Novice, Minerval, and Illuminated Minerval that divided the ranks. The groups secrets were disclosed or published, and the Illuminati disappeared after it was disbanded. However, the myth of the Illuminati has expanded, and many present-day fraternal organizations claim to be descended from the original Bavarian Illuminati and openly use the name "Illuminati". Some of these groups use a variation on the name "The Illuminati Order" in the name of their own organizations, while others, such as the Ordo Templi Orientis, have "Illuminati" as a grade.

In subsequent use, "Illuminati" has been used when referring to various organizations that are alleged to be a continuation of the original Bavarian Illuminati, though these links have not been substantiated. These organizations have often been accused of conspiring to control world affairs, by masterminding events and planting agents in governments and corporations, in order to gain political power, influence, and to establish a New World Order. However, most of the rumors are fiction, and the groups influence was not nearly as vast and enduring as modern conspiracists claim.