Emmeline Pethick was born on 21 October 1867 in Bristol. Her father was a businessman. She was the second of 13 children, and was sent away to boarding school at the age of eight.
From 1891 until 1895 she worked as a "sister of the people" for the West London Mission at Cleveland Hall, near Fitzroy Square. She helped Mary Neal to run the girls club at the mission. In the autumn of 1895 she and Mary Neal left the mission to co-found the Espérance Club, a girls club that 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. She married Frederick Lawrence in 1901 and the pair took the joint name Pethick-Lawrence. She was a member of the Suffrage Society and was introduced to Emmeline Pankhurst in 1906. She became treasurer of the Women's Social and Political Union (WSPU) and raised £134,000 over six years.
Pethick-Lawrence started the publication Votes for Women with her husband in 1907. She was arrested and imprisoned in 1912 for conspiracy following demonstrations that involved breaking windows. After the incident, the Pethick-Lawrences were unceremoniously ousted from the WSPU. They then joined the United Suffragists. Emmeline was present at the Women's Peace Congress in 1915 at the Hague. She stood as Labour candidate for Rusholme, Manchester in 1918.
In 1945 she became Lady Pethick-Lawrence when her husband was made a baron.