The researcher analyzed the language of instruction used by English teacher in senior high schools, especially English teacher at MAN 2 Soppeng, This study aims to find the language of instruction used by teacher in teaching English and the reasons why teacher use it. The researcher used a qualitative approach. The research focused on English teacher at MAN 2 Soppeng, Interview and observation served as the research instruments. Direct interviews with respondents were used to collect data, and some important data were also documented to support this study. Through in-depth interviews, it was revealed that there are three languages of instruction used: Bugis, Indonesian, and English. The use of these three languages is based on the different abilities of the students, where some students are more comfortable using Bugis as their mother tongue. The use of Bugis helps students who are less fluent in Indonesian and English to better understand the subject matter. The main reason for using these three languages is to bridge the gap of understanding among students who have different language backgrounds.The results of this study are expected to provide valuable insights into how teacher create curriculum and training at MAN 2 Soppeng. And teacher can be wise in choosing the language of instruction for students so that students can improve their English language skills and understand the material presented in English. These results can also be the basis for other research aimed at improving the quality of English language teaching at MAN 2 Soppeng.