This article aims to analyse teachers' perceptions of school failure and dropout through a gender perspective in the Portuguese context. The statistical data show that, in most OECD countries, the rates of school failure and dropout are higher for boys than for girls. In Portugal, the difference in the school failure and dropout rates for boys and girls is quite significant, and there is a considerable lack of research. This study used a mixed methods design with both quantitative and qualitative data collection. We used a questionnaire and interviews to explore the teachers' perceptions of school failure and dropout through a gender perspective. The study was based on a performative model, which considers the construction of gender as a continuous and changing process as a result of social interaction in all spaces and at all times of life. We consider that school is a space where gender construction takes place, particularly in the relationships between pupils, and between pupils and teachers, which can have an impact on the pupils' educational achievement. The data collected show that most teachers are not aware of gender differences in school failure and dropout. When confronted with the national statistics, the teachers do not recognise that the phenomenon is taking place in their schools. The teachers consider that gender differences in school failure and dropout result from personal and family factors, external to school and reveal gender stereotypes based on hegemonic masculinity.