Student engagement remains a topical aspect of learning and teaching as it influences student outcomes and learning experiences. It is generally accepted to be a malleable construct encompassing students' actions, feelings and thoughts, all of which are influenced by the learning context and pedagogical choices made by the teacher. The aim of the current study was to investigate secondary teachers' understandings of student engagement in relation to three dimensions (behavioural, emotional and cognitive engagement), and how these understandings align with actual teaching practice. The mixed methods study collected data from six secondary teachers using an online questionnaire, interviews, and classroom observations. It was found that some teachers hold views about student engagement that differ from the practices they implement in their classrooms. The qualitative data suggests that the engagement strategies some teachers implement in the classroom, or feel they can implement, may be influenced by the socio-economic context of a school. Findings contribute novel insights to existing literature about secondary teachers' prioritisation of strategies, and implementation of practices, to foster student engagement in the classroom.