"Aim: To explore experts' views of the key determinants of N&FS knowledge among Australian and Iranian school-leavers. Method: Semi structured interviews were conducted with 49 experienced food-related experts (21 from Australia; 28 from Iran). Thematic analysis was employed to analyze and interpret the qualitative data. Results: The experts believed that schools are appropriate settings for N&FS education. Both Australian and Iranian experts believed that schoolteachers are not well informed about N&FS issues, and the N&FS components of current school curricula are poorly taught, particularly food systems topics and food-related skills. Other identified determinants of school-leavers knowledge by both Australian and Iranian experts were: mass media's activities; geographical location (urban or rural); and parents' knowledge and practices of N&FS issues. Iranian experts cited the attractiveness of food and nutrition topics for students (for e.g. weight management topic vs. food systems issues). Other experts were very concerned about the reliability of information sources that students and school-leavers might access. Conclusion: The findings help to identify neglected components of nutrition and food systems education within school curricula in Australia and Iran. They could assist food and nutrition educators, curriculum developers and related policy makers to improve the N&FS knowledge of school-leavers. Keywords: Determinants, N&FS knowledge, School-leavers, Australia and Iran Key Messages 1. N&FS components of school curricula need to be improved 2. School teachers need to be trained 3. Students' parents need to be trained "