Dungal MacDouall (Duncan Macdowall, Dugald Macdowall), was a 13th–14th-century noble, who was a key figure against Robert de Brus, later King Robert I of Scotland, in Galloway, Scotland. It is alleged that he was captured and released three times by King Robert I.
King Robert I of Scotland's invasion of Galloway in 1307, led by his brother Alexander de Brus and Thomas de Brus, Malcolm McQuillan, Lord of Kintyre, two Irish sub kings and Reginald de Crawford, and composing of eighteen galleys, landed at Loch Ryan. The invasion force was quickly overwhelmed by local forces, led by Dungal MacDouall, who was a supporter of the Balliols, Comyns and King Edward I of England, and only two galleys escaped. All the leaders were captured. Dungal Macdouall summarily executed Malcolm MacQuillan, Lord of Kintyre and the Irish sub kings and had their heads taken to Edward I. Alexander, Thomas and Reginald de Crawford were sent to Carlisle, England, where they were later executed.
Sir Edward Bruce defeated a force commanded by Dungal Macdouall, Sir Ingram de Umfraville and Sir Aymer de St John, during the Battle of the River Dee near Buittle in 1308.
He was captured after Dumfries Castle fell to a siege by forces of King Robert I in 1313. He had been the constable of Dumfries Castle.