Clementina Black (27 July 1853 – 19 December 1922) was an English writer, feminist and pioneering trade unionist, closely connected with Marxist and Fabian socialists. She worked consistently for women's rights at work and for women's suffrage.
Clementina Black was born in Brighton, one of the eight children of the solicitor, town clerk and coroner of Brighton, David Black (1817–1892), and his wife, Clara Maria Patten (1825–1875), the daughter of a court portrait painter. She was educated at home, mainly by her mother, and became fluent in French and German.
In 1875, Clementina's mother died of a rupture caused by lifting her invalid husband, who had lost the use of both legs. Clementina, as the eldest daughter, was left in charge of an invalid father and seven brothers and sisters, as well as doing a teaching job. Her siblings included the mathematician Arthur Black and the translator Constance Garnett. She and her sisters moved in the 1880s to Fitzroy Square in London, where she spent her time studying social problems, doing literary work, and lecturing on 18th-century literature.
Black made the acquaintance of Marxist and Fabian socialists and became a friend of the Marx family. She was involved over a long period with the problems of working-class women and the emerging trade union movement. In 1886, she became honorary secretary of the Women's Trade Union League and moved an equal-pay motion at the 1888 Trades Union Congress. In 1889, she helped to form the Women's Trade Union Association, which later became the Women's Industrial Council.
Black was among the organizers of the Bryant and May strike in 1888. She was also active in the Fabian Society. In 1895 she became editor of Women's Industrial News, the journal of the Women's Industrial Council, which encouraged middle-class women to report on the conditions of work for poorer women. In 1896 she began to campaign for a legal minimum wage. By the early 1900s she was also active in the burgeoning women's suffrage campaign.