Mary E. L. Butler (1874-1920) (Irish: Máire de Buitléir) was an Irish writer and Irish-language activist.
Mary Butler was the daughter of Peter Lambert Butler and the granddaughter of William Butler of Bunnahow, County Clare. She was a close relative of Edward Carson In order to learn Irish she made several visits to the Aran Islands. According to her memoirs, which are in a Benedictine monastery in France, she was converted to the nationalist cause after reading John Mitchel's Jail Journal. From 1899 to 1904 she edited a women's page and also a children's page in the Irish Weekly Independent. She promoted the nationalist cause in both.
She joined the Gaelic League, where she got to know women Irish-language enthusiasts such as Evelyn Donovan, Agnes O'Farrelly and Máire Ní Chinnéide, and spent several years on its executive.
In 1907, she married Thomas O'Nolan, who died in 1913.
She was a close friend of Arthur Griffith and in a letter of condolence which Griffith wrote to her sister from Mountjoy Jail in 1920 he states that Mary Butler was the first person to suggest to him the name Sinn Féin as the title of the new organisation which he had founded.
She died in Rome in 1920 and is buried there.
The Butlers of County Clare were a landowning family that had remained Catholic. Father Peter had been educated in France and was always at home in French as in English or Irish. Mary's mother's family was purely Gaelic. Mary’s mother was Ellen Lambert of Castle Ellen, Co. Galway, and her younger sister Isabella, was mother of Lord (better known as Sir Edward) Carson. Thus Edward Carson, who became the intransigent leader of Ulster unionism was Mary’s cousin.
Mary's early education was first conducted at home and the way was carefully prepared for the masters' tuition. During the Land League agitation of the late 1870s and early 1880s, Butler was educated at Alexandra College, Dublin, a school attended largely by young women of Protestant background, where she had the advantage of having native masters for the French, Italian, and German languages which she studied with enthusiasm. According to "A Life of Mary Butler", a marked characteristic of her young days and one that grew with her growth, was her intense love of home ties. Butler's conversion to nationalism resulted from a chance encounter with the writings of Young Ireland, and like many blossoming cultural nationalists, she immersed herself in the culture of the western part of the country, visiting the Aran Islands on several occasions.