Gaining insight into how critical thinking influences the comprehension of concepts can facilitate students in achieving a more profound and meaningful learning experience. This study aims to investigate the contribution of critical thinking skills to the concept understanding of Class X Senior High School Students at the implementation of the 5E Instructional Model accompanied by the Case Method. This research method uses a correlational research design. The research sample consisted of one Class X Senior High School Student who applied the 5E Instructional Model accompanied by the Case Method. Data analysis using a simple regression correlation test with the help of SPSS for Windows 23. The results showed that students involved in the 5E Instructional Model accompanied by the Case Method experienced significant improvement in their critical thinking skills and concept understanding. This research provides a significant understanding of the dynamic connection between the abilities of critical thinking and the comprehension of concepts among students in senior high school.