Inquiry-based learning is an approach that allows students to draw connections between academic content and their own lives, which can be particularly important for culturally and linguistically diverse learners. The participants of this study were the 48 grade 9 students of Manticao National High School, Pagawan, Manticao, Misamis Oriental. The study sought to find out the effectiveness of Inquiry-based learning approach on the students’ performance in Physics. It aimed to find out the significant difference between the pretest and posttest scores of the students when exposed using Inquiry-based learning approach and Lecture method. The study used the true experimental research design, the randomized pretest-posttest control group design. This study utilized the percentage, independent t-test and paired t-test to analyze the results. Paired t-test revealed a significant difference between the pretest and posttest scores of the students when exposed using Inquiry-based learning approach than of the Lecture method as shown in the mean difference of -3.63 with t-value of -6.70 and p-valueof 0.0000003904 is less than the p-value of 0.05 level of significance and that leads to the rejection of the null hypothesis. This study concluded that an Inquiry-based learning approach can improve the students’ performance in Physics.