Regiae (or Regiæ) was an ancient city and former bishopric in Roman North Africa.
Its presumed location is Arbal, in modern Algeria.
The city was important enough in the Roman province of Mauretania Caesariensis to become a suffragan diocese of its capital Caesarea Mauretaniae's Metropolitan archbishopric.
The diocese was nominally restored as a Latin Catholic titular bishopric in 1933, the Italian Curiate title being Regie.
It has had the following incumbents, all of the lowest (episcopal) rank :