Simone Lucie Ernestine Marie Bertrand de Beauvoir (UK: , US: ; French: [simɔn də bovwaʁ] (listen); 9 January 1908 – 14 April 1986) was a French existentialist philosopher, writer, social theorist, and feminist activist. Though she did not consider herself a philosopher, nor was she considered one at the time of her death, she had a significant influence on both feminist existentialism and feminist theory.

Beauvoir wrote novels, essays, biographies, autobiographies, and monographs on philosophy, politics, and social issues. She was known for her dissertation, The Second Sex (1949), a detailed analysis of women's oppression and a foundational tract of contemporary feminism. She was also known for her novels, the most known including She Came to Stay (1943) and The Mandarins (1954). Her most enduring contribution to literature is her memoirs, notably the first volume, Mémoires d'une jeune fille rangée (1958), which has a warmth and descriptive power. She also was a highly awarded woman, some of the most notable prizes being: 1954 Prix Goncourt, the 1975 Jerusalem Prize, and the 1978 Austrian State Prize for European Literature.