Ethel Mary Smyth (April 23, 1858 - May 8, 1944) was an English composer and a leader of the women's suffrage movement.

She was born in London and studied music in Leipzig. Her works included symphonies, choral works and operas (most famously The Wreckers). However, possibly her best-known work was "The March of the Women" (1911), which became an anthem for the Women's Social and Political Union, to which she belonged.

In 1922, she received the DBE.

From early 1930 on she had a crush on Virginia Woolf, leading to an abundant exchange of letters between the two women.