Purpose: Teachers' responses to students' mistakes vary based on their countries' social culture. We investigated the cultural script in a Mongolian lesson on teachers' responses to students' mistakes. Design/methodology/approach: We employed transcript-based lesson analyses and cultural transcript approaches. We gathered data from a Mongolian lesson and analysed the transcripts, emphasising the students' mistakes. Findings: We avoided drawing conclusions and offering recommendations on the shortcomings of Mongolian lessons because our approach was from a cultural standpoint. The teacher of our research lesson and interviewee teachers placed less emphasis on working with students' mistakes than other elements of teaching. They tended to ignore or merely acknowledge the students' mistakes in order to continue the lesson as planned. During our discussions, we explored the potential relationship between the behaviourist approach and the way teachers handle their students' mistakes. We also considered how the subject matter might influence the types of mistakes. These findings could guide future research in this area. Research limitations/implications: Though we tried to enhance the representativeness of our study with interviews, we were not satisfied with the qualitative analysis. Future research should focus more on conducting interviews and discussions with Mongolian and Japanese educators to incorporate cross-cultural perspectives. It will provide valuable insights for successfully adapting lesson studies in Mongolia. Originality/value: To the best of the authors' knowledge, there has been no international publication on Mongolian lesson studies on students' mistakes. The cultural perspective of Mongolian lessons may be valuable to a global audience given the uniqueness of the Euro-Asian nomadic culture that is fast adapting to urbanisation in the globalising world.