William Maccall (1812–1888) was a Scottish author and Unitarian minister.
Born at Largs, Ayrshire, on 23 February 1812, he was eldest son of John Maccall, a tradesman, and his wife Elizabeth Murdoch. He was intended for the Presbyterian ministry of the Secession Church, and entered Glasgow University in 1837, graduating M.A. in 1833. George Harris was an early influence. He then passed two years in a theological academy at Geneva, but, convinced by Unitarianism, he joined its ministry. He took a position at Greenock, obtained for him by Harris.
Maccall officiated at Bolton, Lancashire (1837–1840), where he was a Chartist opposed to Feargus O'Connor. He had taken on the Moor Lane Chapel congregation founded by Harris, but it dwindled away. He was then at Crediton in Devon (1841–6). He eventually resigned his ministry to concentrate on writing and lecturing.
Coming to London in 1846, Maccall lived first at 4 Carburton Street, and preached, lectured, and wrote for the press. John Stuart Mill gave him introductions to The Spectator and The Critic; he wrote also for the Gentleman's Magazine. The Royal Literary Fund gave Maccall a grant in 1853. He used the pseudonym Atticus, reviewing Ralph Waldo Emerson in The Critic in 1860.
Later Maccall lived in the suburbs of London, and in 1861 settled at Bexley Heath. In 1864 he became the major contributor to the Propagandist and Theological, Social and Political Review, founded by the secularist John Bagnall Bebbington in May of that year, and running to October. The eclectic content drew on Charles Hennell, and Maccall's translations from Ludwig Büchner and Scandinavian writers. Also in 1864 he was writing in the National Reformer, to advocate a National Land League. Maccall found, however, that the freethought circle around George Holyoake had placed him as a pantheist, rather than an atheist.