Physical education (PE) remains the subject in coeducational schools that is most likely to be delivered in gender segregated sessions. Decisions to offer single sex lessons are often underpinned by discourses and practices associated with doing gender that emphasise differences in boys' and girls' attitudes, behaviours, abilities and experiences. This investigation employs the concept of "undoing" gender to explore the possibility for alternative interpretations of the issues emerging in coeducation. Examples of "undoing gender" included evidence of girls' and boys' engaging positively during activities, girls' identification of positive aspects of mixed gender, examples of boys' and girls' similarities and shared experiences and awareness of girl' capabilities. The paper concludes that the emphasis on gender difference in explaining problems associated with coeducation such as teasing, harassment and exclusion can mask the ways that these practices are embedded within the structure and organisation of PE and provides recommendations for working towards gender integration.