The Abbey of St. Vaast was a Benedictine monastery situated in Arras, département of Pas-de-Calais, France.

The abbey was founded in 667. Saint Vedast, or Vaast (c. 453–540) was the first bishop of Arras and later also bishop of Cambrai, and was buried in the old cathedral at Arras. In 667 Saint Auburt, seventh bishop of Arras, began to build an abbey for Benedictine monks on the site of a little chapel which Saint Vedast had erected in honour of Saint Peter. Vedast's relics were transferred to the new abbey, which was completed by Auburt's successor and generously endowed by King Theuderic III, who together with his wife was afterwards buried there.

The Abbey of St. Vaast was of great importance amongst the monasteries of the Low Countries. It was exempt from episcopal jurisdiction and maintained its independence until 1778, when it was aggregated to the Congregation of Cluny.

At the French Revolution it was suppressed and the monastic buildings were used first as a hospital and then as barracks. In 1838 the premises were purchased by the town; part was used as a museum and archive, and the rest as the residence of the bishop. The abbey church, which had been desecrated and partially destroyed, was rebuilt and consecrated in 1833 and now serves as the cathedral of Arras, replacing the former Gothic cathedral destroyed during the Revolution.