Due to the leaky pipeline, i.e., the continuous decline in the number of women along the academic career path, women are still underrepresented in many academic disciplines like STEM and philosophy. One theoretical model that explains this is the lack of fit framework (Heilman, Sex bias in work settings: The lack of fit model; Heilman & Caleo, Combatting gender discrimination: A lack of fit framework). According to this, women in male-stereotyped disciplines perceive a misfit to the person stereotypical for the discipline. This perceived misfit has been associated with a lower sense of belonging and thus less engagement, intention to persist, and probability of choosing a career in the discipline. So far, the Lack of Fit Model has been studied in work and university contexts but not in schools. In the present study, we applied the lack of fit framework to secondary school, focusing on high school students (N = 523) and their perception of philosophy (a highly male-stereotyped discipline). We showed that female high school students have a higher perceived self-philosopher misfit than male high school students. Using a structural equation model, we showed that this gender-discipline misfit correlates with less engagement and lower intention to persist and possibly career choice via a lower sense of belonging. The results extend previous findings on the lack of fit framework to the school context.