<p>Teachers play an important role in identifying their students’ mental health problems through their interaction in school. This study aimed to investigate teachers’ confidence, barriers, and needs in identifying varying forms of mental health problems, their opinions about the feasibility of structured mental health screening in schools, and their opinions regarding training to improve their ability to identify difficulties. Thirty-three Indonesian Junior and Senior high school teachers participated in individual online semi-structured interviews. The data were analysed using reflexive thematic analysis. Seven themes were developed: (1) confidence in assessing student mental health, (2) observable behaviours being easier to assess, (3) teachers use a personal approach to identify mental health problems, (4) reliance on personal experience to deal with students’ mental health problems, (5) the need for social support, (6) the need for a skill improvement program, and (7) mental health screening would be feasible in schools. The findings provide an impetus for designing future training for school-based mental health problem identification for teachers.</p>