Abstract. Full text article available at: https://doi.org/10.1080/18146627.2020.1868070The adoption of the learning management system (LMS) in secondary schools is scaling up around the globe. Many educational institutions use the LMS to mainstream teaching and learning. This study examined the effectiveness of the Moodle LMS in teaching and learning geometry in secondary schools. A quasi- experimental design was employed to generate data from two groups of students: the control group and the treatment group. The treatment groups learned geometry using the developed Moodle LMS while the control group learned geometry using the traditional chalk and talk method. Both the treatment and control groups did pre-test and post-test to track the impact of the intervention. The analysis of covariance (ANCOVA) test was employed to compare the pre-test and post-test scores and to make statistical analysis. The analysis revealed that the students who were taught geometry through the Moodle LMS outperformed those taught geometry through the traditional chalk and talk method. It is established in the study that for students to learn geometry better through the Moodle LMS, the system should be used to start teaching from the first topics of Form I to upper topics. Also, students should be given enough time to access the Moodle LMS to learn mathematics. The study concludes that the integration of the LMS in teaching and learning mathematics is a means by which failure in mathematics can be minimised.