Critical thinking skills are one of the abilities that everyone must have to face the challenges of the 21st century. The use of interactive learning media lectora inspire in discovery learning can facilitate to develop students' mathematical critical thinking skills. Therefore, a study was conducted that aims to see the improvement of critical thinking skills using lectora inspire interactive learning media in the discovery learning model. This research is included in the pre-experimental design with the research design used is a single group one-group pretest-posttest design. The samples used in this study were 26 eighth-grade students in Pekanbaru, Riau. Data analysis techniques using Normality - Gain (N-Gain) test and t-test. The N-gain value obtained was 0.59 with moderate criteria. Based on the T-test results, there is a significant difference in the average pretest score and posttest score. The level of effectiveness occurs in the posttest after using lectora inspire interactive learning media, so the use of lectora inspire interactive learning media in the discovery learning model can improve students' mathematical critical thinking skills. This research makes a significant contribution to the innovation of mathematics learning in Indonesia, by offering a more effective and fun approach. The findings are expected to be a reference for educators, researchers, and educational policy makers in an effort to enhance the quality of mathematics learning.