Arthur II (born 1262—died 1312, Château de l’Isle, near La Roche-Bernard, Brittany) was the duke of Brittany (1305–12), son of John II and Beatrice of England.
By successive marriages before his accession, he acquired the viscounty of Limoges (1275) and the county of Montfort-l’Amaury (1292). During his short reign, the war between Edward I of England and Philip IV of France was ended by treaty, whereby France ceded Brittany to England; but Arthur, with the vigorous support of the Bretons, defied and aborted the transfer. Arthur was succeeded by his son, John III the Good.