This study project examined the utilization of Differentiated Instruction (DI) by English teachers and validated their methodologies to gain further insights into teachers' perceptions and practices through a qualitative approach. The data in this research was collected using four instruments: document analyses, classroom observations, questionnaires, and interviews. Data on teachers' practices of DI was collected through the use of document analyses and classroom observations. In the meantime, in order to obtain data on teachers' perceptions and practices of DI, questionnaires have been used. Last, interviews have been conducted to determine teachers' perceptions. First, an analysis of the data showed that there are some things that teachers could do better, ·even though they are committed to using development intervention methods. By looking at the syllabi, it was clear that teachers had not been setting DI principles that were tailored to each student's needs, as they just followed the established ones they had gotten from the English Teachers' Association. There were also problems with how assessments were matched up with the different ways that students learn, even though teachers had done a great job of making sure that students could learn in the best way for them. In addition, the questionnaires showed how the teachers felt about DI, and all three of them had a good knowledge of its goals and principles. But there were differences between teachers in the level of skills they had and the places where they could improve, especially in terms of adapting instruction to students' learning styles. Second, from each teacher's interview, it was revealed that they showed a strong comprehension of DI that aligned with scholarly views. Teachers with varied levels of expertise and time constraints agreed that DI integration was difficult. They agreed that DI involved students, met a variety of learning needs, and created a positive learning environment. Therefore, this current study showed that teachers need ongoing support and professional development to promote DI use. It also demonstrated the importance of focusing on specific areas for improvement, such as ensuring assessments reflect what students learn and tailoring instruction based on their learning styles.