The introduction of new accountabilities and techniques of government for the purposes of educational reform have created new complexities and tensions for school leadership. Policies such as the publishing of league tables in the UK, high stakes testing in the US and the introduction of the "My School" website in Australia are particularly significant for school principals. In this article I appeal to the work of Foucault and Deleuze to provide an alternate approach to understanding how principals are constituted as subjects through a range of practices and discourses associated with the introduction of the "My School" website. I specifically draw upon Foucault's notion of governmentality and Deleuze's notion of societies of control to provoke new lines of thought into these government practices. I argue that it is through the performative in the education system that school principals are becoming perpetually assessable subjects.