Ralph Erskine (18 March 1685 – 6 November 1752) was a Scottish churchman. Ralph Erskine was the son of Henry Erskine. He was also the younger brother of another prominent churchman, Ebenezer Erskine.He was chaplain and tutor to the 'Black' Col. John Erskine from 1705 to 1709. After studying at the University of Edinburgh, Ralph was ordained assistant minister at Dunfermline in 1711. He ratified the protests which his brother laid on the table of the assembly after being rebuked for his synod sermon, but he did not formally withdraw from the establishment till 1737.