"The Well of Loneliness" is a lesbian novel by British author Radclyffe Hall that was first published in 1928 by Jonathan Cape. It follows the life of Stephen Gordon, an Englishwoman from an upper-class family whose "sexual inversion" (homosexuality) is apparent from an early age. She finds love with Mary Llewellyn, whom she meets while serving as an ambulance driver in World War I, but their happiness together is marred by social isolation and rejection, which Hall depicts as typically suffered by "inverts", with predictably debilitating effects. The novel portrays "inversion" as a natural, God-given state and makes an explicit plea: "Give us also the right to our existence".

Radclyffe Hall (18801943) was an English poet and author, best known for the novel The Well of Loneliness, a groundbreaking work in lesbian literature. In adulthood, Hall often went by the name John, rather than Marguerite.