<![CDATA[Critical thinking skills are essential for navigating the challenges of the 21st century. However, PISA study results indicate that the critical thinking skills of students in Indonesia remain low. One approach to fostering these skills is the development of innovative teaching materials, specifically Problem-Based Learning (PBL)-based Electronic Student Worksheets (E-LKPD). This study aimed to develop a PBL-based E-LKPD on the digestive system to train the critical thinking skills of 11th-grade high school students. The research employed the 4D development model, comprising four stages: Define, Design, Develop, and Disseminate. The study evaluated three parameters: validity, practicality, and effectiveness. Validity was assessed by education and subject matter experts; practicality was determined through observations of lesson implementation and student response questionnaires; and effectiveness was measured by the achievement of critical thinking indicators. Research instruments included validation sheets, observation sheets, response questionnaires, and test questions. A limited trial involved 36 students from class XI F-11 at SMA Negeri 3 Sidoarjo. The resulting product features eight key components: Bio-Orientation, Bio-Organizer, Bio-Experiment, Bio-Activity, Bio-Anaeva, Bio-Quiz, Bio-Explore, and Bio-Presentation. The results showed an E-LKPD validity score of 95.83% (highly valid); lesson implementation and student response scores of 99.3% and 100%, respectively (highly practical); and critical thinking indicator achievement rates of 34.8% on the pre-test and 87.8% on the post-test, with an N-Gain score of 0.82 (high category). In conclusion, the PBL-based E-LKPD is deemed suitable as a teaching material for fostering critical thinking skills, based on its demonstrated validity, practicality, and effectiveness.]]>
