Emmeline Pethick-Lawrence, Baroness Pethick-Lawrence (née Pethick; 21 October 1867 – 11 March 1954) was a British women's rights activist, suffragist and pacifist. She was a leading member and treasurer of the Women's Social and Political Union (WSPU), organised WSPU's first Week of Self-Denial and founded and edited the publication Votes for Women. She was ousted from the WSPU for her opposition to more militant action and founded the United Suffragists. She was one of the first members of the Women's International League for Peace and Freedom (WILPF) and she led a campaign against the naval blockade on Germany during World War I.

Pethick-Lawrence was born in 1867 in Clifton, Bristol as Emmeline Pethick. Her father, Henry Pethick, of Cornish farming stock, was a businessman and merchant of South American hide, who became owner of the Weston Gazette, and a Weston town commissioner. She was the second of 13 children, five who died in infancy, and her younger sister, Dorothy Pethick (the tenth child), was also a suffragist.

Pethick was sent away to the Greystone House boarding school in Devizes, Wiltshire, at the age of eight. She was reluctant to conform from an early age and got into trouble frequently at school. She was then educated at private schools in England, France and Germany.

From 1891 to 1895, Pethick worked as a "sister of the people" for the West London Methodist Mission at Cleveland Hall, near Fitzroy Square, having been inspired by Walter Besant's book The Children of Gibeon (1886). She ran a girls' club at the mission with Mary Neal and they became friends and lived together.

In 1895, she and Neal left the mission to co-found the Espérance Club, with support from the evangelical Christian socialist Mark Guy Pearse. The club for young women and girls would not be subject to the constraints of the mission, and could experiment with dance and drama. Pethick also started Maison Espérance, a dressmaking cooperative with a minimum wage, an eight-hour day and a holiday scheme, and was founder of the Social Settlement for Girls from the East End of London.

Pethick met wealthy barrister Frederick William Lawrence in 1899 at Percy Alden's Mansfield House settlement in Canning Town. She feared that a conventional marriage with him would curtail her independence and prevent her from her social service work, so turned down his first marriage proposal. After a second proposal, they married on 2 October 1901 at Canning Town Hall, three weeks before her 34th birthday.

After the marriage, the couple took the hyphenated joint surname Pethick-Lawrence as a gesture of equality, and kept separate bank accounts to give them financial autonomy. They moved to Holmwood, near Dorking and also shared a London flat. Between 1906 and 1912 Holmwood would become a central meeting place for leaders of the suffrage campaign and a refuge where suffragettes could recover from forcible feeding. On their first wedding anniversary, Frederick gave her the key to a private flat on the roof of Clement's Inn for her own private use.

During a visit to South Africa with her husband, Pethick-Lawrence read about Christabel Pankhurst and Annie Kenney's protest and unfurling a banner declaring "Votes for Women" at the Manchester Free Trade Hall in October 1905, and their subsequent arrest. Back in Britain, Pethick-Lawrence became a member of the Suffrage Society and was introduced to Emmeline Pankhurst by politician Keir Hardie in 1906. Pethick-Lawrence became treasurer of the Women's Social and Political Union (WSPU), which Pankurst had founded in 1903, and raised £134,000 over six years. Her husband and Keir Hardie also donated funds to pay off the organisations debts and she insisted that her friend and chartered accountant Alfred Sayers be appointed to audit the WSPU finances.