Christadelphians affirm a literal, earthly millennium (or extended age of Christ's kingdom) during which Christ will reign from Jerusalem over the nations, with the redeemed saints serving as his co-regents. This is understood not as a 1,000-year interlude before the end of history but as the fulfillment and culmination of God's covenantal purposes for the earth — the restoration of all things that the Old Testament prophets anticipated.

The Christadelphian millennial vision is closely tied to their understanding of the Abrahamic and Davidic covenants. God promised Abraham the land of Canaan as an everlasting possession (Genesis 12, 17) and David that his dynasty would be established forever (2 Samuel 7). Christ, as the ultimate heir of Abraham and the Son of David, will fulfill these promises literally: the land will be restored to Israel, the nations will come to Jerusalem to learn God's ways, and swords will be beaten into plowshares.

This earthly, Israel-centered millennialism is a defining feature of Christadelphian eschatology and distinguishes it from amillennialism (which spiritualizes the millennial promises) and from some forms of dispensationalism (which place the millennium as a distinct prophetic period after the rapture). For Christadelphians, the millennium is not a separate dispensation but the culmination of the one covenant of grace made with Abraham.