Schneiderman helped found the New York branch of the Women's Trade Union League, a pivotal organization advocating for women workers' rights.
In 1903, Rose Schneiderman became a founding member of the New York branch of the Women's Trade Union League (WTUL), a cross-class alliance of working-class and middle- and upper-class reformers dedicated to improving conditions for female wage earners. The WTUL sought to organize women into trade unions, lobby for protective labor legislation, and educate the public about the plight of working women.
This was a critical moment for Schneiderman, who by this time had already begun organizing her fellow cap makers into a union after finding that the male-dominated United Cloth Hat and Cap Makers Union was reluctant to admit women. Her leadership in organizing women workers caught the attention of established reformers, and she quickly rose to prominence within the League.
The WTUL became one of the most important vehicles for early twentieth-century labor feminism in the United States, and Schneiderman would go on to serve as president of the New York WTUL from 1917 to 1919 and president of the National WTUL from 1926 to 1950. Her involvement from its founding placed her at the center of decades of advocacy for minimum wage laws, maximum hour legislation, and safer working conditions, cementing her legacy as one of the most significant labor organizers of her era.