<![CDATA[Differentiated instruction is a key approach in implementing the Merdeka Curriculum because it requires teachers to accommodate students’ diverse learning readiness, interests, learning profiles, and learning needs. However, in practice, Indonesian language teachers still face various challenges in implementing differentiated instruction in the classroom, particularly in managing a heterogeneous student body, limited time for lesson planning, and limited learning resources and facilities. These conditions can hinder teachers from providing learning experiences tailored to the needs of each student. This study aims to describe the challenges faced by Indonesian language teachers in implementing differentiated instruction across the aspects of content, process, product, and learning environment at Siak Hulu State High School 2. The novelty of this study lies in its comprehensive examination of the challenges in implementing differentiated instruction through these four aspects, while also revealing the relationship between teachers’ instructional practices and school support in the context of Indonesian language instruction under the Merdeka Curriculum. This study employs a qualitative approach using a descriptive method. Data were collected through in-depth interviews with four Indonesian language teachers and document analysis. Data validity was ensured through source triangulation, while data analysis utilized the Miles and Huberman interactive model, which includes data reduction, data presentation, and the drawing and verification of conclusions. The results indicate that teachers face challenges across all aspects of differentiated instruction. These challenges include time constraints in lesson planning, difficulties in identifying students’ learning needs, managing heterogeneous classrooms, developing fair assessment rubrics for various learning products, and limitations in learning resources, facilities, and technological support. In addition, differences in student characteristics and a lack of school support also influence the implementation of differentiated instruction. The findings of this study provide practical implications for improving the quality of differentiated instruction through continuous professional development for teachers, the provision of adequate learning facilities, and the strengthening of collaboration between teachers and schools. This study contributes to providing a contextual overview for schools and policymakers to develop more responsive and sustainable differentiated instruction practices that accommodate the diversity of students’ learning needs.]]>
