The Diocese of Arras (–Boulogne–Saint-Omer) is a Latin Church diocese of the Catholic Church in France. The episcopal see is the Arras Cathedral, in the city of Arras. The diocese encompasses all of the Department of Pas-de-Calais, in the Region of Hauts-de-France.

Arras is the prefecture of the Pas-de-Calais department, which forms part of the region of Hauts-de-France; before the reorganization of 2014 it was in Nord-Pas-de-Calais. The historic centre of the Artois region, with a Baroque town square, Arras is in northern France at the confluence of the rivers Scarpe and Crinchon.