This thesis aims to explore the categories of sexuality and gender through an analysis of Jeanette Winterson&rsquo / s well-known novels, Oranges Are Not the Only Fruit and Written on the body, against the background of Butler&rsquo / s concept of performativity and Cixous&rsquo / s &eacute / criture feminine. By underlining the constructedness of these categories and questioning the boundaries of patriarchal concepts and transgressing them, Winterson deconstructs the binary oppositions created by phallocentric discourse and problematizes the verdict that sexuality is inborn. Instead of this ingrained notion, she asserts that gender and sexual identities are culturally and discursively constructed by the dominant discourse. Although the dominant discourse favors heterosexuality over homosexuality and degrades sexuality into a binary frame of oppositions such as masculinity/ feminity and male/female, Winterson, in her novels, seeks an alternative to escape this ideological binarism and achieves to subvert the binary oppositions by highlighting the fluidity of sexuality and gender, and by creating amorphous characters like the ungendered narrator in Written on the body or by bestowing on them bisexuality or homosexuality as in Oranges Are Not the Only Fruit. Hence, the main argument of this thesis will be to display Winterson&rsquo / s deconstruction and dissolution of the patriarchal categories in her novels and to emphasize her escape from the binary charade, in a fictional universe, with references to Butlerian performativity and Cixousian &eacute / criture feminine.