"God is dead" (German: Gott ist tot [ɡɔt ɪst toːt] ^ⓘ; also known as the death of God) is a statement made by the German philosopher Friedrich Nietzsche. The first instance of this statement in Nietzsche's writings is in his 1882 The Gay Science, where it appears three times. The phrase also appears in the first section, that titled the Prologue, of Nietzsche's Thus Spoke Zarathustra, and again in Chapter 25, The Pitiful, of the longer portion, Zarathustra's Discourses.

The meaning of this statement is that since, as Nietzsche says, "the belief in the Christian God has become unbelievable", everything that was "built upon this faith, propped up by it, grown into it", including "the whole [...] European morality", is bound to "collapse".

Other philosophers had previously discussed the concept, including Philipp Mainländer and Georg Wilhelm Friedrich Hegel. The phrase is also discussed in the Death of God theology.

Discourses of a "death of God" in German culture appear as early as the 17th century and originally referred to Lutheran theories of atonement. The phrase "God himself is dead" also translated as "God himself lies dead" ("Gott selbst liegt tot"), appears in the Lutheran hymn by Johann von Rist "Ein Trauriger Grabgesang" ("A mournful dirge"), also named "O Trauigkeit, O Herzeleid" ("Oh sadness, Oh heartache).

Before Nietzsche, the phrase 'Dieu est mort!' ('God is dead') was written in Gérard de Nerval's 1854 poem "Le Christ aux oliviers" ("Christ at the olive trees"). The poem is an adaptation into a verse of a dream-vision that appears in Jean Paul's 1797 novel Siebenkäs under the chapter title of 'The Dead Christ Proclaims That There Is No God'. In an address he gave in 1987 to the American Academy of Arts and Sciences, the literary scholar George Steiner claims that Nietzsche's formulation 'God is dead' is indebted to the aforementioned 'Dead Christ' dream-vision of Jean Paul.

The phrase is also found in a passage expressed by a narrator in Victor Hugo's 1862 novel Les Misérables:

"God is dead, perhaps," said Gerard de Nerval one day to the writer of these lines, confounding progress with God, and taking the interruption of movement for the death of Being.

Contemporary historians believe that 19th-century German idealist philosophers, especially those associated with Georg Wilhelm Friedrich Hegel, are responsible for removing the specifically Christian resonance of the phrase relating to the death of Jesus Christ and associating it with secular philosophical and sociological theories.