The Kalergi Plan, sometimes called the Coudenhove-Kalergi Conspiracy, is a debunked far-right, antisemitic, white genocide conspiracy theory. The theory claims that Austrian-Japanese politician Richard von Coudenhove-Kalergi, creator of the Paneuropean Union, concocted a plot to mix and replace white Europeans with other races via immigration. The conspiracy theory is most often associated with European groups and parties, but it has also spread to North American politics.

The white genocide, white extinction, or white replacement conspiracy theory is a white supremacist conspiracy theory that claims there is a deliberate plot to cause the extinction of whites through forced assimilation, mass immigration, and/or violent genocide. It purports that this goal is advanced through the promotion of miscegenation, interracial marriage, mass non-white immigration, racial integration, low fertility rates, abortion, pornography, LGBT identities, governmental land-confiscation from whites, organised violence, and eliminationism in majority white countries. Under some theories, Black people, Hispanics, and Muslims are blamed for the secret plot, but usually as more fertile immigrants, invaders, or violent aggressors, rather than as the masterminds. A related, but distinct, conspiracy theory is the Great Replacement theory.