Her Father’s Name (1876) is one of Marryat’s most radical and intriguing novels, featuring Leona Lacoste, a cross-dressing heroine, and Lucilla Evans, a textbook hysteric who falls in love with her. For centuries, the diagnosis of ‘hysteria’ was conveniently applied to any woman who exhibited transgressive behaviour, whether it be through sexual promiscuity or simply by expressing strong opinions. As I argue in this paper, Marryat uses her novel to reveal how in the late nineteenth century, hysteria was clearly linked with lesbianism and used to pathologise sexual deviance. Using the character of a family doctor, Marryat shows how the medical profession operated to regulate gender, expose artifice, and restore patients to ‘normative’ sexuality. I discuss how the doctor is thwarted by the willingness of the other characters to collude in Leona’s disguise – they accept both her transvestism and her often reciprocal attraction to women. Whereas in many contemporary novels masculine women are feared and derided as vectors of lesbian contagion, Leona is portrayed as an entirely sympathetic character. Through her, Marryat allows women a greater range of sexual expression, presenting lesbianism as an alternative to heterosexual marriage, rather than as an ugly subversion of the feminine ideal. Leona’s protean nature, I propose, allows Marryat to explore radical ideas in what is, on the surface, a pantomimic text, but one that yields deeply subversive readings. In Leona she presents a heroine who comprehensively challenges prevailing notions of both femininity and sexuality.