The enormous economic and demographic as well as political changes experienced by early modern England were registered in the social fabric as acute anxiety about the breakdown of conventional hierarchies, especially female transgression against traditional gender roles. As gender was a significant way of representing social relations, the playwrights of early modern England dramatized unstable gender relations and explored assumptions about women in their plays. Shakespeare, in particular, examined patriarchal authority and its limits as well as the responses of women to this authority and their limits in his plays. This paper focuses on Portia`s transgression of the rigid divisions of gender roles. In The Merchant of Venice, Portia represents an androgynous ideal; she refuses to accept conventional stereotypes for female behaviour. Transvestite Portia proves herself a more potent man in the court scene than any of her masculine characters through her resourceful manipulation and legal argument. Her transvestism, attendance at the court, cuckoldry jokes and financial management all constitute much threat to the patriarchal order. However, Shakespeare apparently resolves the threat to the comic world that Portia herself embodies when she returns the ring to her husband in the end. Through her ability which was thought to belong to men only, we can conclude that gender roles are not fixed by nature but by culture and institution.