Nowadays, students in every school are familar in using technology in the process of gaining new knowledge. However, students' perceived activeness in the learning process plays an important role in learning success. In every lesson, students are required to understand the basic concepts of each material, including in mathematics geometry. Reflecting on the results of the Checkpoint for Lower Secondary exam in 2022/2023, grade VIII students still got unsatisfactory scores in mathematics, especially in geometry. So we will develop augmented reality-based learning media using Assemblr Edu to increase students' understanding of geometry and to increase student activity in learning mathematics in class.This research uses the ADDIE method which includes analysis, design, development, implementation and evaluation. To collect the data, this research uses questionnaires, tests and observation methods which will be analyzed qualitatively and quantitatively. The implementation of the learning media developed involved 63 students in grade VIII at Unity Junior High School, Bekasi City, academic year 2023/2024 and 3 Mathematics teachers. The results of this research show that the level of students' understanding of geometry is 80.18% and the level of student’s activeness level is 89.6%.With these results, the product is declared feasible and can be used as a new learning media in mathematics lesson.