Ruth Valborg Maria Gustafson née Pettersson (8 July 1881 – 5 April 1960), was a Swedish politician (Social Democrat), union worker, women's rights activist and editor.
She was a member of the National Association for Women's Suffrage from 1902 to 1921, and a speaker of the left wing within the movement.
Ruth Gustafson was born to caretaker Fredrik Teodor Pettersson and Anna Lovisa Johansson in Stockholm.
Gustafson was raised in an intellectual working-class home with parents interested in socialism and worker's rights and a father engaged in union work, and she became active in the social democratic movement through its youth clubs in Stockholm in the 1890s.
She was known for her radical views in favor of abolishing the church, in favor of civil marriage, to give legal rights to couples living together without being married (as she herself did with her spouse for six years before she married him), and to protect children from being used for child labor.