Sylvia was born in Baltimore, Maryland, as Nancy Woodbridge Beach. When she was six months old her family moved to Bridgeton, New Jersey, where her father was the pastor of the Presbyterian church. When Sylvia was 15 the family moved to Paris for three years.

She returned in Paris two years later, in 1917 , and here she met Adrienne Monnier, the woman who was to be her lover and close friend throughout her life - they lived together for 20 years. She was the original publisher of James Joyce's Ulysses when no other publisher would have it.

Sylvia Beach opened in Paris, in 1919, a bookshop with English literature "Shakespeare and company". In 1941 the Germans occupied Paris and she closed the bookshop on short notice, moving all of its content to safety before taking refuge with friends in Touraine, where she remained sequestered until after the war. Beach then returned to Paris where, after Monnier's suicide in 1955, developed a new relationship with Camilla Steinbrugge. Beach lived in Paris until her death.