William Johnson Fox (1 March 1786 – 3 June 1864) was an English religious and political orator.
Fox was born at Uggeshall Farm, Wrentham, near Southwold, Suffolk on 1 March 1786. His parents were strict Calvinists. When he was still young, his father quit farming. After time at a chapel school, Fox became a weaver's boy, an errand-boy, and in 1799, a bank clerk. An autodidact, he entered prize competitions.
From September 1806 Fox trained for the Independent ministry, at Homerton College. His tutor there was John Pye Smith, the Congregational theologian. Early in 1810 he took charge of a congregation at Fareham in Hampshire. Failing to make a small seceding congregation there viable, he left within two years to become minister of the Unitarian chapel at Chichester.
In 1817 Fox moved to London, becoming minister of Parliament Court Chapel. In 1824 he moved the congregation to South Place Chapel, in Finsbury on the edge of the City of London, which had been built specifically for him. Around Fox and the chapel there gathered a group of progressive thinkers, including feminists and, through William Lovett, some adherents of Chartism. The circle included Sophia Dobson Collet, who saw some of Fox's sermons into print;Mary Leman Gillies, who wrote on women's rights; and Caroline Ashurst Stansfeld, whose marriage to James Stansfeld was conducted by Fox. Fox's position as a leading Unitarian minister was jeopardized in 1834-5 when he left his wife for one of his wards, and became an advocate of freer divorce. This eventually resulted in a secession of fifty families from the Chapel, Fox's resignation from the Unitarian ministry, and a new household for him in the Craven Hill area of Bayswater. He re-established himself as a preacher of rationalism. Charles Hardwick grouped Fox with Theodore Parker and Robert William Mackay as proponents of "absolute religion". Fox's public presence became increasingly that of a commentator on social and political matters. The South Place chapel itself eventually lost its identification with Unitarianism, becoming the South Place Ethical Society.