This research is aimed to improve students’ critical thinking through guided inquiry-based learning on the topic of material and its changes. This research was conducted on 50 students of class 7 in Junior High School. Within the framework of this research to improve the critical thinking skill student’s uses guided inquiry-based learning. The researcher used pretest-posttest one group design to find out students’ critical thinking skill. Based on the research revealed that guided inquiry-based learning is effective to improve students’ critical thinking skill. It is indicated by the high result of the N-gain category. According to the results, it can be implied that guided inquiry-based learning is effective to improve students’ critical thinking skill.