William Auld (6 November 1924 – 11 September 2006) was a Scottish poet, author, translator and magazine editor who wrote chiefly in Esperanto. Auld was born at Erith in Kent, and then moved to Glasgow with his parents, attending Allan Glen's School. After wartime service in the RAF, he studied English Literature at Glasgow University, and then qualified as a teacher.
In 1960 he was appointed to a secondary school in Alloa and he remained there for the rest of his life. He was nominated for the Nobel Prize in Literature in 1999, 2004, and 2006, making him the first person nominated for works in Esperanto.
His magnum opus, La infana raso (The Infant Race), is a long poem that, in Auld's words, explores "the role of the human race in time and in the cosmos," and is based heavily on The Cantos by Ezra Pound.
Auld began to learn Esperanto in 1937 but only became active in the propagation of the language in 1947, and from then on wrote many works in Esperanto. He edited various magazines and reviews, including Esperanto en Skotlando (1949–1955), Esperanto (1955–1958, 1961–1962), Monda Kulturo (1962–1963), Norda Prismo (1968–1972), La Brita Esperantisto (1973–1999) and Fonto (1980–1987).
He was the Vice-President of the World Esperanto Association (1977–1980), president of the Academy of Esperanto (1979–1983), and president of the Esperanto PEN Centre (1999-2005). In 2001, he donated his large personal collection of Esperanto literature to the National Library of Scotland, where it is now housed.