Simone de Beauvoir wrote several philosophical treatises and was one of the contributors to the development of existentialism. De Beauvoir wrote novels in addition to philosophical works making feminist ideas more accessible to all. She is best known for “The Second Sex” which she published in 1949, about the condition of women. This is a pivotal work in 20th century feminism, and despite some limitations, survives the test of time. In this presentation, we will look at the life of Simone de Beauvoir and her theoretical and feminist contributions to 20th century thought.