Australian Journal of Guidance and Counselling 21(2): 126-141 Abstract Introduction: Anxiety and depression in adolescence is prevalent but often unrecognised and untreated. This can lead to serious disorders in later life. This study explored how teachers recognise anxiety and depression in secondary school students and act on their concerns. Method: Twenty teachers from four secondary colleges in regional Victoria, Australia were interviewed regarding their experiences. In-depth interviews were analysed using descriptive thematic analysis in order to understand how teachers respond to this issue. Results: Teachers’ recognition of mental health problems in students and the threshold for reporting their concerns was subjective and not based on any formal knowledge of how to identify anxiety or depression risk factors in students. Years of teaching experience was not associated with increased knowledge of mental health problems in students. Time pressures and lack of resources in student wellbeing teams were barriers to teachers reporting their concerns about students. Conclusion: Education bodies and teaching universities responsible for training teachers and providing ongoing professional learning need to ensure that mental health training is part of every teacher’s core skill set, so that teachers can confidently promote mental wellbeing, identify emerging mental health problems, know how to facilitate access to more specialist intervention where required and contribute effectively to follow-up support.