The Diocese of Beja (Latin: Dioecesis Beiensis) is a Latin Church diocese of the Catholic church in Portugal.

[2] Beja lies on the site of Pax Julia, or Paca, of the Romans, and is still surrounded by remains of old Roman walls, partly restored.

Beja was taken from its Islamic rulers in 1162 by Afonso I of Portugal.

Beja Cathedral is an old church, much modernized, of uncertain date.

[3] The chronicler Isidorus Pacensis, of the eighth century, was traditionally said to have been bishop of Beja; but this is now disputed.