Introduction. Facing the maintenance of gender inequalities in school, the return of single-sex education is a perspective discussed and already in place in some countries. To teach physical education (PE) in single-sex versus coeducational contexts is widely internationally debated (Hills & Croston, 2012). In coeducational schools, PE remains the subject that is most likely to be delivered in gender segregated sessions (e.g., England, Finland, Switzerland, Belgium). Described as a new educational option, the single-sex classes aim to achieve more successful outcomes and to eradicate gender violence between girls and boys. However, educational research on single-sex classes PE is inconclusive (Hannon & Williams, 2008). Nowadays, studies on single-sex classes PE are limited, particulary those focusing on a qualitative and empirical approach. The purpose of this study was to explore more in depth a single-sex PE class and identity the gender construction through the analysis of boys’ activity.