William Thomasson (trade unionist)

William Thomasson (born circa 1824, died after 1891) was a British trade unionist, notable for his long tenure as General Secretary of the Amalgamated Association of Operative Cotton Spinners, Twiners and Self-Actor Minders.

Thomasson rose through the ranks of the Operative Cotton Spinners' union in Bolton, eventually becoming the district secretary. In 1859, he succeeded the previous General Secretary, James Mawdsley (the elder), and relocated to Manchester to manage the union's national affairs.

During his leadership, Thomasson navigated the cotton industry through periods of economic boom and bust, including the Cotton Famine of the 1860s caused by the American Civil War. He advocated for negotiation and arbitration in industrial disputes, generally favoring peaceful resolution over strike action, though he did support strike action when deemed necessary to protect members' interests.

Thomasson was a key figure in the development of trade unionism in the cotton industry, promoting the amalgamation of smaller, localized unions into the larger Amalgamated Association. His focus was on strengthening the union's financial position and improving the living and working conditions of cotton spinners through collective bargaining. He also played a role in lobbying for legislative reforms affecting the industry and working conditions. He retired from his position in 1891. His place of death is unknown, but it is likely he remained in Lancashire.