Gertrude Stein was born in Allegheny, Pennsylvania, on February 3, 1874, to wealthy German-Jewish immigrants. At the age of three, her family moved first to Vienna and then to Paris. They returned to America in 1878 and settled in Oakland, California. Her mother, Amelia, died of cancer in 1888 and her father, Daniel, died 1891.

Stein attended Radcliffe College from 1893 to 1897, where she specialized in Psychology under noted psychologist William James. After leaving Radcliffe, she enrolled at the Johns Hopkins University, where she studied medicine for four years, leaving in 1901. Stein did not receive a formal degree from either institution.

In 1903, Stein moved to Paris with Alice B. Toklas, a younger friend from San Francisco who would remain her partner and secretary throughout her life. The couple did not return to the United States for over thirty years.

Together with Toklas and her brother Leo, an art critic and painter, Stein took an apartment on the Left Bank. Their home, 27 rue de Fleurus, soon became gathering spot for many young artists and writers including Henri Matisse, Ezra Pound, Pablo Picasso, Max Jacob, and Guillaume Apollinaire.

She was a passionate advocate for the "new" in art, her literary friendships grew to include writers as diverse as William Carlos Williams, Djuana Barnes, F. Scott Fitzgerald, James Joyce, and Ernest Hemingway. It was to Hemingway that Stein coined the phrase "the lost generation" to describe the expatriate writers living abroad between the wars.

By 1913, Stein's support of cubist painters and her increasingly avant-garde writing caused a split with her brother Leo, who moved to Florence. Her first book, Three Lives, was published in 1909. She followed it with Tender Buttons in 1914.

Tender Buttons clearly showed the profound effect modern painting had on her writing. In these small prose poems, images and phrases come together in often surprising ways—similar in manner to cubist painting. Her writing, characterized by its use of words for their associations and sounds rather than their meanings, received considerable interest from other artists and writers, but did not find a wide audience.

Sherwood Anderson in the introduction to Geography and Plays (1922) wrote that her writing "consists in a rebuilding, and entire new recasting of life, in the city of words."

Among Stein's most influential works are The Making of Americans (1925); How to Write (1931); The Autobiography of Alice B. Toklas (1933), which was a best-seller; and Stanzas in Meditation and Other Poems [1929-1933] (1956).

In 1934, the biographer T. S. Matthews described her as a "solid elderly woman, dressed in no-nonsense rough-spun clothes," with "deep black eyes that make her grave face and its archaic smile come alive."

Stein died at the American Hospital at Neuilly on July 27, 1946, of inoperable cancer.