This paper explores the policy of single-sex classes that is currently being adopted in some schools as a strategy for addressing boys educational and social needs. It draws on research in one Australian government, coeducational primary school to examine teachers' and students' experiences of this strategy. Interviews with the principal, male and female teachers responsible for teaching the single-sex classes and the students involved in these classes are used to illustrate the impact and effect of the strategy on pedagogical practices in this particular school. The data are used to raise critical questions about the impact and effects of teachers' pedagogical practices in light of the current literature and research about single-sex classes. In this case study, it was found that teachers had a tendency to modify their pedagogical practices and the curriculum to suit stereotypical constructions about boys' and girls' supposed oppositional orientations to learning. It is concluded that teacher knowledges and assumptions about gender play an important role in the execution of their pedagogies in the single-sex classroom. (Contains 4 endnotes.)