This study aimed at describing the use of Code-Switching by teachers in teaching English at MAS Ulumul Qur’an. Code-Switching is a phenomenon of language switching, in this case between English and Indonesian, which is often used by teachers as a communication strategy to help students' understanding. This study used a descriptive qualitative approach with data collection techniques in the form of classroom observation, semi-structured interviews with teachers and students of interview transcripts. The use of Code-Switching is done for various purposes, including explaining difficult material, giving instructions, attracting students' attention, and creating a more interactive classroom atmosphere. This research is expected to contribute to the development of more communicative and contextualized learning strategies in English classes. The results of the study show that teachers use code-switching not only as a means to simplify concepts that are difficult for students to understand, but also as a tool to build emotional closeness in communicating with students. By combining Indonesian and English, teachers are able to adapt their communication style to the needs and ability levels of their students. This helps to create a more inclusive learning environment, where students feel more confident to actively participate in class activities. Furthermore, interviews with students revealed that the use of code-switching had a positive impact on their motivation to learn. Students felt helped when teachers delivered explanations in a language they were familiar with, making the learning process more efficient and enjoyable. This study identified the most frequently used code-switching patterns by teachers, including intra-sentential and inter-sentential switching between languages. Thus, this study provides practical contributions for English teachers in designing teaching methods that are more adaptive, communicative, and appropriate to the classroom context in Indonesia.