This study was conducted to determine the effectiveness of IBT in Geometry as well as its impact on learning and attitude of grade 7 Junior High School at Talayan National High School. IBT module in grade 7 geometry was used as an intervention to 74 IBT class covering the third quarter of the school year 2019- 2020. True experimental (IBT class and Non IBT class) and descriptive design were utilized in the study. Result revealed the significant findings that majority of the respondents in IBT class got improvement in their Geometry test scores from pre- test to post test in remembering (43 or 58%), understanding (44 or 59.4%), applying (44 or 59.4%), analyzing (40 or 54.1%), evaluating (46 or 62.2%) and creating (47 or 63.5%). Majority of the Non IBT Class in geometry have no improvement in their pre-test and post test in geometry in the categories; remembering (43 or 57.4%), understanding (54 or 72.1%), applying (53 or 70.7%), analyzing (40 or 53.4%), evaluating ( 37 or 49.3%) and creating (34 or 45.3 %). This signifies that conventional approach in teaching is less effective than the IBT approach. Result showed significant difference in the mean gain scores between Inquiry- Based Teaching Class (x̄= 0.92) and non- Inquiry Based Teaching class (x̄= 0.25) as indicated in the difference (F- value= 10.853 and p-value= 0.000). Hence, IBT is effective in teaching geometry. Result also revealed that most students strongly agree on the perceptions on use, impact and their attitudes in using IBT.