"Ni dieu ni maître!"—Neither God nor master!—is a phrase coined by the socialist Auguste Blanqui in 1880, when he published a journal by that name. It became an anarchist slogan.

Louis-Auguste Blanqui (1805-1881) was nick-named " l'enfermé "—"locked up"— because over half of his adult life was spent in jail. He was involved in failed insurrections in 1839, 1840, and 1870. His supporters, known as "Blanquists", made up a substantial faction of the Paris Commune insurrection of 1871. Blanqui supported the notion of class struggle, spearheaded by an elite "revolutionary vanguard" of intellectuals, on behalf of the workers, the proletariat, against the bourgeoisie, the middle class. While somewhat influential in France, his theories obtained practical efficacy when adopted by Vladimir Lenin and the Russian Bolsheviks for their own particular revolutionary brand of Marxism.

The phrase pops up in a couple of places in Friedrich Nietzsche's Beyond Good and Evil, first in Section 22, in a critique of the notion that "nature" dictates a morality of equality before the law—"natural law"—and then again in Section 202, where he identifies it as both an anarchist slogan and the motto of "herd morality", the morality of compassion for others—which Nietzsche apparently did not consider to be a good and noble thing.

Blanqui's phrase has particular resonance for anarchists in Portugal, Spain, France, and other places where a reactionary Catholic Church hierarchy was deeply involved in government and devoted all its resources to counterevolution. In such places, it was difficult not to conflate religion with slavery.