Background: Research suggests that students and teachers often tend to diverge in their perceptions of instructional practices that are part of their everyday classroom experience. This might include differing views about assessment and feedback, or the effectiveness of task design. Accordingly, there is a need to understand as much as possible about the reasons for such differences. Purpose: Whilst it is important to investigate students' and teachers' views on the reasons for these differences, the present study aimed to contribute to the 'why' and 'how' behind student-teacher divergence in perception by specifically focusing on teachers' perspectives. Method: A total of 398 Austrian secondary school teachers responded to an open response question in an online survey. They were invited to reflect on the possible reasons for student-teacher divergence in terms of perceptions of instruction. The teachers' statements written in response to the question were analysed, in detail, using qualitative content analysis. Data were grouped according to micro, meso and marcrolevel factors. Findings: Analysis gave rise to a detailed categorisation of the reasons given by teachers, from their viewpoints, for student-teacher divergence in perception. The resultant categories and subcategories revealed a wide range of explanations, including sociodemographic, motivational and emotional factors, and consideration of classroom features, and environmental factors. Conclusions: As the themes that emerged were largely consistent with factors discussed in previous literature, the findings offer further in-depth insight into the possible underlying mechanisms, as well as highlighting some newly identified explanations, from teachers' viewpoints, for student-teacher divergence in perception. The study generates some new ways to think about why teachers and students may have different perceptions of everyday instructional practices in the classroom, and draws attention to the significance of this complex area for all concerned with strengthening the quality of teaching and learning.