在基督教末世论中，千禧年后论（postmillennialism）是对启示录20章的一种解释，认为基督再临发生在基督徒繁荣、占优势的千年王国之后。这种观点与 千禧年前论（premillennialism）相对，较小程度上与无千禧年论（amillennialism）相对。

虽然一部分千禧年后论者按照字面认为千年王国真的是一千年，但是大部分千禧年后论者认为一千年是一个象征，代表很长的时期（类似无千禧年论）。他们通常认为千年王国已经开始，这意味着一种不太明显、较少戏剧性的千年王国类型，而不是千禧年前论所认为的基督会突然回来。

In Christian end-times theology (eschatology), postmillennialism is an interpretation of chapter 20 of the Book of Revelation which sees Christ's second coming as occurring after (Latin post-) the "Millennium", a Golden Age in which Christian ethics prosper. The term subsumes several similar views of the end times, and it stands in contrast to premillennialism and, to a lesser extent, amillennialism (see Summary of Christian eschatological differences).