Ruaraidh Erskine of Marr (15 January 1869 – 5 January 1960) (Scottish Gaelic: Ruaraidh Arascain is Mhàirr) was a Scottish nationalist political activist, writer and Scottish Gaelic language campaigner.
Ruaraidh Erskine was born The Honourable Stuart Ruaraidh Joseph Erskine at 1 Portland Place, Brighton, East Sussex, England on 15 January 1869. He was the third of the four children born to William Macnaghten Erskine, 5th Baron Erskine (1841–1913), an army officer, and his wife, Caroline Alice Martha Grimble. The family were descendants of the Erskine Earls of Buchan.
Erskine learned to speak Scottish Gaelic from his childhood nanny, who came from Harris, and this kindled the enthusiasm which was to be a main hallmark of his career. His imagination was fired early by the Irish nationalist movement and these combined influences, together with his family's Scottish roots, led to his development as a prominent Gaelic nationalist, whose compelling dream was of a self-governing Celtic Scotland. As essential steps towards the realization of this dream he was actively involved in the fostering of Gaelic consciousness and in the extension of Gaelic usage, especially in the written form. He hoped that a significant extension of Gaelic literary range would contribute to the raising of literary standards, in a reaction against what he saw as the down-grading influence of music-hall and ‘pop’ culture on Gaelic verse in the second half of the nineteenth century. He probably also viewed his activity as a response to the dominance of folk culture in the Gaelic literary world.
In 1892, aged 23, he became vice-president of the Scottish Home Rule Association, but he grew to oppose the notion of home rule for Scotland within the United Kingdom and went on to support Scottish independence.