The International Ladies' Garment Workers' Union (ILGWU), whose members were employed in the women's clothing industry, was once one of the largest labor unions in the United States, one of the first US unions to have a primarily female membership, and a key player in the labor history of the 1920s and 1930s. The union, generally referred to as the "ILGWU" or the "ILG", merged with the Amalgamated Clothing and Textile Workers Union in the 1990s to form the Union of Needletrades, Industrial and Textile Employees (UNITE). UNITE merged with the Hotel Employees and Restaurant Employees Union (HERE) in 2004 to create a new union known as UNITE HERE. The two unions that formed UNITE in 1995 represented 250,000 workers between them, down from the ILGWU's peak membership of 450,000 in 1969.

The New York shirtwaist strike of 1909, also known as the Uprising of the 20,000, was a labour strike primarily involving Jewish women working in New York shirtwaist factories. It was the largest strike by female American workers up to that date. Led by Clara Lemlich and the International Ladies' Garment Workers' Union, and supported by the National Women's Trade Union League of America (NWTUL), the strike began in November 1909.