Sir Dunbar Plunket Barton, 1st Baronet PC (29 October 1853 – 11 September 1937) was an Anglo-Irish British politician, author and judge.

Nephew of the Anglican Archbishop of Dublin, Barton was a sincere Protestant, but exceptionally tolerant in all matters of religion: Maurice Healy recalled him quoting a saying of his father that whether one is a Protestant or a Catholic is largely a chance of birth.

When Barton was a boy, his father instructed him to guess the distance between his mother's bedroom window and the window at the home next door, to which he guessed 20 ft. "Well, my boy," his father told him, "You are a Protestant; but always remember that if you had been born 20 ft. to the east you would have been a Catholic.

He served as an Irish Unionist Member of Parliament (MP) for Mid Armagh from 1891 to 1900 and was Solicitor-General for Ireland for two years (1898–1900).

He was created a baronet of Fethard in the County of Tipperary on 28 January 1918:[4] since his only son predeceased him the title became extinct at his death.