The study on English language teaching in multilingual education policy has been widely investigated in public and private schools in many countries. In Indonesia, while such a policy exists, such as in an Islamic boarding school, the topic is still relatively under-researched. This study then explores the implementation of English language teaching on multilingual education policy in a public Islamic boarding senior high school. Additionally, it also looks at the teachers' beliefs and practices regarding the implemented policies.

Using a mini- ethnographic case study as the research methodology, I collected data from a series of observations, follow-up in-depth interviews, pictures of school and classroom activities and linguistic schoolscapes, and artifacts, such as teaching and policy documents, as the basis for the thematic data analysis. While the study focuses on English teacher and multilingual teachers at the school, other stakeholders at the school were also involved in the study, such as principals, and school administrators.

This study reveals that teachers taught their students based on their beliefs on multilingual education and their capacity as teachers at the school instructed to use different languages with the students at the school. In other words, they were playing a crucial role as agents of the school's multilingual education policy. While all the teachers in this study showed their commitment to implementing the policy and helping their students learn and use Indonesian, English, Arabic, and Javanese, they also admitted that they were not active agents of the policy. This research provides insights into what policymakers and school stakeholders need to carefully consider when implementing such a teaching English in multilingual education policy at an Islamic boarding school in Indonesia and beyond.