Old Norse religion, also known as Norse paganism, is a branch of Germanic religion which developed during the Proto-Norse period, when the North Germanic peoples separated into a distinct branch of the Germanic peoples. It was replaced by Christianity and forgotten during the Christianisation of Scandinavia. Scholars reconstruct aspects of North Germanic Religion by historical linguistics, archaeology, toponymy, and records left by North Germanic peoples, such as runic inscriptions in the Younger Futhark, a distinctly North Germanic extension of the runic alphabet. Numerous Old Norse works dated to the 13th-century record Norse mythology, a component of North Germanic religion.

Germanic paganism or Germanic religion refers to the traditional, culturally significant religion of the Germanic peoples. With a chronological range of at least one thousand years in an area covering Scandinavia, the British Isles, modern Germany, and at times other parts of Europe, the beliefs and practices of Germanic paganism varied. Scholars typically assume some degree of continuity between Roman-era beliefs and those found in Norse paganism, as well as between Germanic religion and reconstructed Indo-European religion and post-conversion folklore, though the precise degree and details of this continuity are subjects of debate. Germanic religion was influenced by neighboring cultures, including that of the Celts, the Romans, and, later, by the Christian religion. Very few sources exist that were written by pagan adherents themselves; instead, most were written by outsiders and can thus present problems for reconstructing authentic Germanic beliefs and practices.