Women's Freedom League (act. 1907–1961), was a militant women's suffrage society formed by socialist dissidents from the Women's Social and Political Union (WSPU). The founding members of the WSPU were socialists, including a former teacher, Teresa Billington-Greig, the first woman organizer for the Independent Labour Party, who subsequently became a WSPU organizer. She and other socialist suffragists, including the veteran philanthropist Charlotte Despard, opposed the increasingly autocratic leadership of Emmeline Pankhurst and her daughter Christabel, and changes to WSPU policy after the Pankhursts moved its headquarters to London in 1906. Christabel Pankhurst announced at the Cockermouth by-election in the autumn of 1906 that militant suffragists would no longer support Labour Party candidates, as had been the case in the general election earlier that year. Emmeline Pankhurst confirmed this change of policy at the Independent Labour Party's annual conference in 1907. But this same conference heard a declaration from Despard and other socialists in the WSPU that they intended individually to continue working for Labour candidates. Billington-Greig had the previous year drafted the constitution of the WSPU, but Emmeline Pankhurst now scrapped it and cancelled the annual meeting planned for September 1907. The socialist dissidents then called a conference attended by most of the WSPU's branches, but failed to gain control of its London headquarters and funds. So Billington-Greig, Despard, and Edith How Martyn, another socialist suffragist, established the Women's Freedom League (WFL). Its name, Billington-Greig subsequently suggested, indicated among its members a wider conception of women's emancipation than simply gaining the vote, one that recognized the particular disabilities of women generally, and of working-class women in particular.

Other early members included Nina Boyle, who became head of the political and militant department, Amy Hicks, who became literary secretary (though she later rejoined the WSPU), Elizabeth Knight, who became treasurer, the doctor Octavia Margaret Sophia Lewin (1869–1955), Hannah Mitchell, Margaret Wynne Nevinson, and Annie Cobden-Sanderson. Examples of the league's strong presence in Scotland were Anna Munro, who was Billington-Greig's secretary, Eunice Murray, a member of the executive, Nannie Brown, and Jenny McCallum.

The WFL declared itself a new 'militant' body, that is, it continued for a time to identify more closely with the WSPU than with the ‘constitutionalists’ of the National Union of Women's Suffrage Societies. ‘Militancy’ was never a unitary, unchanging, or uncontested alternative approach to suffrage campaigning, however. It began with what has been termed 'the politics of disruption' during the party-political campaigning that preceded the 1906 general election, and with acts of civil disobedience that resulted in imprisonment. Subsequent to the Liberal election landslide, militants attempted to demonstrate popular support for women's suffrage, principally through the organization of large demonstrations, alongside continuing active opposition to Liberal candidates in the by-elections that then followed the appointment of a new government. From 1908 WSPU militancy additionally involved open, then clandestine attacks, first on government property, then on the persons of ministers, and finally against private property also. To the 'argument of the stone' in window-breaking, militants subsequently added the use of dog whips, hatchets, arson, and bombs.

The retention of a militant character confronted the WFL with two problems: the difficulty of establishing an identity distinct from the WSPU, and the very varied attitudes among its members to the changing nature of militancy, especially where harm or potential harm to persons was involved. In consequence its leadership was constantly trying to identify distinctive forms of militancy that would also maintain unity among its membership. The closeness of the league to suffrage organizations among writers, artists, and the theatre ensured its effective contributions to the various spectacles for which the movement became famous, in processions, pageants, drama, posters, and cartoons. Among the actresses active in the league were Edith Craig, Cicely Hamilton, and Maud Sennett. Its members were initially successful, too, in introducing fresh forms of spectacle, like the showering of London with leaflets from a hot air balloon by Muriel Matters [see Porter, Muriel Lilah Matters-] and the interruption of parliamentary proceedings when she and Helen Fox chained themselves to the grille that screened the ladies' gallery above the House of Commons. Alison Neilans (1884–1942) and the American-born actress Alice Chapin (b. 1862/3) inadvertently injured an official during an attack using acid at a polling booth in 1909, however. The public response prompted the National Union of Women's Suffrage Societies finally to distance itself altogether from militancy.

The WFL, like the WSPU, declared a 'truce' when hopes were high that the private-member Conciliation Bills introduced in 1910 and 1911 might gain further facilities in the House of Commons and enfranchise women. In this period the league developed a distinctive approach that it termed ‘constitutional militancy’, one encouraging civil disobedience, notably in the form of tax-resistance, the interruption of court proceedings where the charges represented the sexual oppression of women, and non-co-operation with the 1911 census. The south Wales organizer of women teachers, Emily Phipps, was among those who boycotted the census, while Emma Sproson, a member of the national executive, was twice imprisoned for keeping a dog without a licence. This shift moved it closer to the National Union of Women's Suffrage Societies, especially after the WSPU turned to the use of still greater violence after the Conciliation Bill was 'torpedoed' by the Liberal government's announcement in November 1911 of a proposed manhood suffrage bill. Like the constitutionalists, too, the league now sought to attack the government by supporting Labour candidates in three-cornered elections. This period saw the resignation of Billington-Greig, disillusioned with militancy and arguing the inadequacy of suffrage reform alone for achieving the emancipation of women. Other members were increasingly uneasy at Despard's insistence on following her own path, whatever the formal policy of the WFL.

After the outbreak of war in August 1914 the WFL declared its intention of maintaining its campaign for women's suffrage, alongside its other objectives, including the protection of working women, which drew in figures like Fanny Parker. The WSPU, by contrast, ceased campaigning, while the National Union of Women's Suffrage Societies immersed itself in the relief of the immediate distress occasioned by the war, attempting thereby to avoid any identification with anti-war movements and awaiting the revival of the debate on franchise reform. By 1916 the issue of the enfranchisement of soldiers at the front saw the establishment of a speaker's conference on suffrage reform, and the national union recommenced its pressure-group activities. The WFL too pressed for women's suffrage, though its preference now was for giving the vote to all adult men and women. In the event, the Registration Act of 1918 was a compromise that enfranchised women over thirty but fell short of full sexual equality in the suffrage, for all men over twenty-one might qualify on registering for a vote. Despard was defeated when she stood for parliament in the election that followed. While other suffrage groups now disbanded or changed names and programmes, the WFL survived until 1961, playing a part in the campaign for the 1928 act that finally brought women full equality in the franchise, and continuing to pursue its broader goal of full sexual equality within British laws and institutions. Recruits in this later phase included the internationalist Margery Irene Corbett Ashby and the equal-pay campaigner Stella Newsome, who wrote the league's fiftieth-anniversary history. Its last president, Marian Reeves, had joined in 1909 and on her death the WFL was dissolved.