The Women's Library is England's main library and museum resource on women and the women's movement, concentrating on Britain in the 19th and 20th centuries. It has an institutional history as a coherent collection dating back to the mid-1920s, although its "core" collection dates from a library established by Ruth Cavendish Bentinck in 1909. Since 2013, the library has been in the custody of the London School of Economics and Political Science (LSE), which manages the collection as part of the British Library of Political and Economic Science in a dedicated area known as the Women's Library.

The printed collections at the Women's Library contain more than 60,000 books and pamphlets, more than 3,500 periodical titles (series of magazines and journals), and more than 500 zines. In addition to scholarly works on women's history, there are biographies, popular works, government publications, and some works of literature. There are also extensive press cutting collections.

The Library's museum collection holds more than 5,000 objects, including over 100 suffrage and modern campaigning banners, photographs, posters, badges, textiles, and ceramics. There are more than 500 personal and organisational archives, ranging in size from one to several hundred boxes.

In February 2007, the Women's Library collections were designated by the Museums, Libraries and Archives Council for their "outstanding national and international importance" (the Designation Scheme is now overseen by the Arts Council). In 2011, items from the women's suffrage archives held at The Women's Library were inscribed in UNESCO's UK Memory of the World Register as the "Documentary Heritage of the Women's Suffrage Movement in Britain, 1865–1928".

The Women's Library traces its roots to the London Society for Women's Suffrage, a group established in 1867 to campaign for the right to vote. The "core" collection was the Cavendish-Bentinck library that was founded in 1909 by Ruth Cavendish Bentinck. The collection was organised by the inaugural librarian, Vera Douie, who was appointed on 1 January 1926. At this time, and for many years afterward, it was called the Women's Service Library, in accordance with the name of the society which since the outbreak of World War I had been called the London Society for Women's Service. Douie remained in post for 41 years, during which time she took a small but interesting society library and turned it into a major resource with an international reputation.

It was originally housed in a converted public house in Marsham Street, Westminster, which in the 1930s was developed into Women's Service House, a major women's centre within walking distance of Parliament. Members of the society and library included writers such as Vera Brittain and Virginia Woolf, as well as politicians, most notably Eleanor Rathbone. Woolf wrote about the Library to Ethel Smyth: "I think it is almost the only satisfactory deposit for stray guineas [money]".

During World War II it suffered bomb damage, and the library had no permanent home until 1957, when it moved to Wilfred Street, near Victoria railway station. By this time, the society and library had changed their names to the Fawcett Society and the Fawcett Library, in commemoration of the non-militant suffrage leader Millicent Garrett Fawcett, and of her daughter, Philippa Fawcett, an influential educationist and financial supporter of the society.

In the 1970s, the Fawcett Society found it increasingly difficult to maintain the library. In 1977, it was taken over by the City of London Polytechnic. Coincidentally the move to the Polytechnic's library was overseen by Rita Pankhurst who was Sylvia Pankhurst's daughter-in-law. That polytechnic became, in 1992, London Guildhall University. The library subsequently spent nearly 25 years in a cramped basement increasingly liable to flooding, while increasing considerably its stock, its user base and its contacts with other such resources both nationally and internationally.