五大牧首区（古希腊语：Πενταρχία，英语：Pentarchy），基督教历史上的术语，源自于初代教会首领将整个罗马帝国的领土，统一在唯一的基督教会（Christendom）的理想。这些地区分别被划归为五个主教座，由五个宗主教进行管理。这五个教会分别位于罗马、君士坦丁堡、亚历山大港、安条克和耶路撒冷。将普世与唯一的统治权力归于基督教会手中的理念，与罗马帝国统治结构之间有紧密的关连，但是因为地区政治及教会势力的现实状况，造成五大教区的分划。这五个主教座比起其他主教座拥有更大权力，是因为它们在政治和教会的重要性；它们全都位于帝国内的重要城市和区域，也是教会的主要中心。罗马、亚历山大和安条克在早期教会发展有重要角色。君士坦丁堡在4世纪成为皇室首都，因此名列罗马之后。耶路撒冷在使徒时期十分重要，因此获得礼仪上的排位。

"Pentarchy" (from the Greek Πενταρχία, Pentarchia from πέντε pente, "five", and ἄρχειν archein, "to rule") is a term in the history of Christianity for the administration of all Christendom by the heads (Patriarchs) of the five major episcopal sees of the Roman Empire: Rome, Constantinople, Alexandria, Antioch, and Jerusalem. The idea came about because of the political and ecclesiastical prominence of these five sees, but the concept of their universal and exclusive authority was firmly tied to the administrative structure of the Roman Empire. The pentarchy was first tangibly expressed in the laws of Emperor Justinian I (527–565), particularly in Novella 131. The Quinisext Council of 692 gave it formal recognition and ranked the sees in order of preeminence. Especially following Quinisext, the pentarchy was at least philosophically accepted in Eastern Christianity, but generally not in the West, which rejected the Council, and the concept of the pentarchy.