This paper derives from a larger study, looking at how students in one secondary school in Ontario problematised and understood gender expression. This study applies a Foucaultian analytic framework of disciplinary space to the problem of the bathroom in public schools. It focuses specifically on the surveillance and regulation of gendered bodies within such a space. How young people understand the surveillance of their bodily presence is significant in terms of how they are constituted as a gendered subject. I use Foucault's [1977. "Discipline and punish" (translated by Alan Sheridan). New York: Vintage Books, Random House, Inc; 1980. "Power-knowledge: Selected interviews and other writings, 1972-1977" (Colin Gordon, ed.) (translated by Colin Gordon ... [et al.]). Hassocks: Harvester Press] concept of subjectivation to investigate how a subject is formed through mechanisms of disciplinary power, as well as Butler's [1990. "Gender trouble: Feminism and the subversion of identity." New York: Routledge] "gender performativity" theory to trouble the notion of gender in non-binary, unfixed terms. Additionally, the public toilet space itself can be theorised using queer theory and trans studies, particularly in terms of conceptualising the washroom as a regulated space. (Contains 7 figures and 1 note.)