Dr. O'Dowd is a 1940 British drama film directed by Herbert Mason, produced by Sam Sax for Warner Bros and starring Shaun Glenville, Peggy Cummins, Felix Aylmer and Irene Handl. Set in Ireland, it focuses on Marius O'Dowd, an Irish doctor, who works to restore his relationship with his son after his daughter-in-law dies under O'Dowd's care. The film was the onscreen debut for Peggy Cummins, who was only thirteen at the time. It was well received by critics, and Cummins' role was the subject of particular praise. The film is currently missing from the BFI National Archive, and is listed as one of the British Film Institute's "75 Most Wanted" lost films.

Samuel George Herbert Mason was a British film director, producer, stage actor, army officer, presenter of some revues, stage manager, stage director, choreographer, production manager and playwright. He was a recipient of the Military Cross the prestigious award for "gallantry during active operations against the enemy." He received the gallantry award for his part in the Battle of Guillemont where British troops defeated the Germans to take the German stronghold of Guillemont.