Fictional secrets that shape characters’ behaviour and choices, advance plot, and engage readers, occupy a prominent position in Edith Wharton’s novels. In The House of Mirth (1905), The Fruit of the Tree (1907), The Custom of the Country (1913) and Summer (1917), the fictional secrets of women serve as a lens for contemporary concerns that affect them disproportionately and involve, variously, illicit affairs, marriage and divorce, pregnancy and individual agency. This chapter’s comparative analysis of the life histories of women’s secrets considers the moment of revelation to the reader, followed by instances of secrets being protected by secret owners or keepers, their discovery by other characters, exploitation and/or confession. While revealing a fair degree of variability across texts, this approach makes apparent Wharton’s interest in portraying women’s secrecy purely as a defence mechanism, but also gestures towards the potential reward of withholding information. A further line of enquiry in this chapter, folded into the discussion of Wharton’s treatment of fictional secrets, involves her use of women’s secrets as part of a gendered impressionist aesthetic. She employs undisclosed details, fractured chronologies and open endings that encourage readers to enter into an impressionist collaboration with her.