This paper examines the portrayal of Blanche DuBois’s sexuality and its connection to patriarchy in Tennessee Williams’s A Streetcar Named Desire. In this critically acclaimed play, Blanche not only performs her assigned gender role but also flaunts her sexuality which transgresses gendered norms of her society. Critics mostly agree that because of repressive patriarchal rules she loses her sanity, while few argue that her excessive sensuality causes her downfall. Instead of perceiving patriarchy as a catalytic backdrop, or an instigating agent, this paper aims to view Blanche’s descent into madness as the sheer plotting of patriarchy since her transgressive sexuality upsets the patriarchal status quo. Using the lens of Gender and Sexuality Studies, it argues how transgressive female sexuality poses a threat to the existing chauvinist power structure. It also seeks the tools patriarchy uses to control and cage transgressive female sexuality, discussing how the discourse of insanity and maternity is manipulated to bring back order on stage, and in the society in general.