Premillennialism, in Christian eschatology, is the belief that Jesus will physically return to the Earth before the Millennium, heralding a literal thousand-year messianic age of peace. Premillennialism is based upon a literal interpretation of Revelation 20:1–6 in the New Testament, which describes Jesus's reign in a period of a thousand years.

Christian eschatology is a minor branch of study within Christian theology which deals with the doctrine of the "last things", especially the Second Coming of Christ, or Parousia. Eschatology – the word derives from two Greek roots meaning "last" (ἔσχατος) and "study" (-λογία) – involves the study of "end things", whether of the end of an individual life, of the end of the age, of the end of the world, or of the nature of the Kingdom of God. Broadly speaking, Christian eschatology focuses on the ultimate destiny of individual souls and of the entire created order, based primarily upon biblical texts within the Old and New Testaments. Christian eschatology looks to study and discuss matters such as death and the afterlife, Heaven and Hell, the Second Coming of Jesus, the resurrection of the dead, the rapture, the tribulation, millennialism, the end of the world, the Last Judgment, and the New Heaven and New Earth in the world to come.