The United Nations Sustainable Development Goals (SDGs) Target 4.7 stated that by 2030, all learners should acquire the knowledge and skills needed to promote sustainable development. However, only scattered studies outline how SDG knowledge has been taught in public K12 curricula. This study aims to identify SDG topics in 13 subjects in the Hong Kong Diploma of Secondary Education curriculum and the perceptions of teachers in relation to SDG education. Data were collected through a machine learning approach and semi-structured interviews. Analysis of the module, subject, and curriculum level was conducted. By examining how teachers perceive in relation to the results of SDG classification and implementation of SDG education, the findings showed that teachers and administrators have adopted positive attitudes towards SDG classification, and supportive government can positively influence teachers and administrators in implementing SDG education. Such findings can be useful for policymakers to develop strategies to facilitate SDG education. © The Author(s) 2023.