Narthex

For the plant known in antiquity as narthex, see Ferula communis.

Plan of a Western Christian cathedral, with the narthex in the shaded area at the western end.

The narthex of St. Patrick's Church in Lowell, Massachusetts. The entrance to the church building itself, along with the entrance to the nave is visible in this photograph.

The narthex is an architectural element in Christian churches consisting of the area reached after opening the church doors; one or three doors in the narthex then open into the nave of the church.

The narthex in the floor plans of Christian churches dates back to early Christian and Byzantine basilicas and churches, which consisted of the narthex (entrance or vestibule), located at the west end of the nave, opposite the church's main altar. In early Christian churches the narthex was often divided into two distinct parts: an esonarthex (inner narthex) between the west wall and the body of the church proper, separated from the nave and aisles by a wall, arcade, colonnade, screen, or rail, and an external closed space, the exonarthex (outer narthex), a court in front of the church façade delimited on all sides by a colonnade as in the first St. Peter's Basilica in Rome or in the Basilica of Sant'Ambrogio in Milan. The exonarthex may have been either open or enclosed with a door leading to the outside, as in the Byzantine Chora Church.

The area outside the entrance of the church (which leads into the narthex) may include a covered porch.