School girls in Sweden are reported to develop psychological (ill)health in relation to their school behaviour and over-achievements. The methods offered as prevention and treatments are aimed at the individual girl's self-management of stress, health and psychological state, putting the responsibility on the girls themselves. This feminist agential realist study aims to explore how the material-discursive school environment, that is, the entanglement of architecture, materialities, bodies, discourses and discursive practices--including the discourses on girls' health in research and media texts--are collectively responsible for, co-constitutive of and enacting female students' ill- and well-being. Doing a diffractive analysis, we register how we as researchers are involved and co-productive of this complex apparatus of knowing of school-related ill-/well-being. A diffractive analysis aims to not only analyse how this apparatus is made and what it produces, but also how it can be productive of new possible realities that might produce more livable school environments.