This article discusses the results of a qualitative ethnographic study in a secondary school in Greece. The study explored teacher-student classroom interaction in a mixed-ability group in a working-class school in Greece. It also explored the links between the teachers' behaviour in the classroom and their ideas about gender and, to a limited extent, their life experiences. Although the sample was small and there were many variations, the findings of the study suggest that overall teachers behaved differently towards girls and boys. Teachers' general lack of awareness or low level of awareness of gender as an important organising and categorising factor in students' behaviour and generally in schooling, as well as the teachers' tacit assumptions about gender, influenced the way that teachers related to girls and boys in the classroom. Other issues, such as the lack of teachers' training on equal opportunities, the low status of the school and the principal's lack of involvement in the promotion of gender equality in the school, also impact on teacher-student interaction.