<![CDATA[Critical thinking is one of the essential competencies that should be developed in Islamic Religious Education (IRE) in accordance with the objectives of the Merdeka Curriculum. However, its implementation still faces various challenges because the learning process tends to be teacher-centered, limiting students' opportunities to construct knowledge independently. This study aimed to describe the implementation of constructivist learning theory in developing students' critical thinking skills in Islamic Religious Education for eleventh-grade students at SMAN 10 Gowa. This study employed a qualitative approach using a case study design. The research participants consisted of an Islamic Religious Education teacher, eleventh-grade students, and school administrators selected through purposive sampling. Data were collected through classroom observations, in-depth interviews, and documentation, and were analyzed using the Miles, Huberman, and Saldaña interactive model, including data condensation, data display, and conclusion drawing and verification. Data validity was ensured through source, technique, and time triangulation. The findings revealed that the implementation of constructivist learning theory was carried out through problem-based apperception, group discussions, presentations, question-and-answer sessions, and reflective activities, enabling students to actively construct their own knowledge. This approach contributed to the development of students' critical thinking skills, as demonstrated by their ability to analyze problems, present arguments, evaluate information, and draw independent conclusions. The successful implementation was supported by teachers' readiness, students' enthusiasm, and school support, while the main obstacles included students' lack of self-confidence, differences in academic abilities, limited instructional time, and students' previous dependence on teacher-centered learning. Therefore, constructivist learning theory can be regarded as an effective and relevant approach for creating active, meaningful, and student-centered Islamic Religious Education learning while fostering students' critical thinking skills.]]>
