This thesis examines female gender nonconformity as a behaviour in response to Victorian patriarchal oppression in the female protagonist of Charlotte Brönte's bildungsroman Jane Eyre. Gender nonconforming behaviour is depicted as behaviour that does not obey gender roles or expectations, linking the responsive quality of such behaviours to the traits of hegemonic masculinity exerted by the male characters who represent and perpetuate a patriarchal system: St John Rivers and Edward Rochester. The investigation concludes that not only Jane but also Bertha endure and suffer the oppression that triggers their gender nonconforming behaviours. This thesis has not examined Bertha as an antagonistic version of Jane, nor as the monster in the angel and monster dichotomy which Gilbert and Gubar have pointed out, but as a future version of her. It is concluded as well that Jane is spared of Bertha's destiny because of Rochester's degraded physical condition which does not allow him to assert his dominance over Jane as he did over Bertha. Jane perpetuates the dehumanisation of Bertha to an extent given Bertha's creole ethnicity and dark traits, which Jane uses to demonize Bertha by characterizing her as a wild creature.