The Union of Factory Workers (French: Union Centrale des Travailleurs de Fabrique, Dutch: Centrale der Fabriekwerkers) was a general union in Belgium. Various local unions of factory workers formed in Belgium around the turn of the 20th-century. In 1908, Christ Mahlman attempted to unite these unions as the Belgian Factory Workers' Union. This struggled, but was refounded in 1910 as the "Union of Factory Workers", affiliated to the Trade Union Commission. Initially a small organisation, with only 3,500 in 1913, it grew rapidly during World War I, and by 1920 it had 51,283 members.