Miss Jessel is Bly’s previous governess who died before the events of the novel. Her character is present within the narrative only via spoken rumor and possible supernatural appearances. The governess only knows what Miss Jessel was like while alive through the gossip of Mrs. Grose. According to her, Miss Jessel was a young and beautiful lady who came from a well-to-do family. Owing to her youth and privilege, Miss Jessel apparently lacked the discipline needed to monitor the children. Despite her social status, Miss Jessel had an illicit and scandalous affair with Bly’s valet, Peter Quint. This affair tarnished Miss Jessel’s reputation, both because sexual promiscuity is seen as unbecoming of a lady and because Quint was of a lower class than she.

As a ghost, Miss Jessel serves alongside Peter Quint as one of the story’s antagonists. Having been described as young and beautiful in life, Miss Jessel takes on a pale and horrific appearance in death. Although her intentions are unclear, the governess deduces that Miss Jessel’s ghost is focused on monitoring, connecting with, and potentially corrupting Flora. The reader can gather that some sort of possession takes place between Miss Jessel’s ghost and Flora—or at least, that the governess believes this to be so—as Flora adopts a cold and nasty attitude towards the governess after several encounters with Miss Jessel. Once Flora is removed from Bly to heal from an illness, what happens to the ghost of Miss Jessel—if, indeed, she existed at all—remains a mystery.