This study is a development research aimed at producing a GeoGebra-based mathematics learning media grounded in the Van Hiele theory to support the teaching and learning of maximum and minimum values. The 4-D development model (define, design, develop, disseminate) was employed, though the study was implemented only up to the third phase (develop). Data were collected through expert validation instruments, practicality questionnaires administered to both teachers and students, and an effectiveness test. Both qualitative and quantitative descriptive analyses were applied to interpret the data. The research was conducted at SMA Negeri 2 Padangsidimpuan with a small-scale trial involving nine participants. The developed media was evaluated based on three key criteria: validity, practicality, and effectiveness. Results indicated high validity, with average scores of 4.67 (on a 5-point scale) from media experts and 4.30 from subject-matter teachers—both categorized as “very high.” Practicality was also rated highly: teachers reported a practicality percentage of 97.75%, while students reported 90%, both falling into the “very high” category. Furthermore, the effectiveness test revealed a student mastery rate of 88.89%, demonstrating the media’s capacity to facilitate meaningful learning outcomes. These findings confirm that the GeoGebra-based learning media, integrated with the Van Hiele theoretical framework, satisfies the standards of validity, practicality, and effectiveness for teaching maximum and minimum values in secondary mathematics. The dynamic visualization and structured cognitive progression aligned with Van Hiele’s levels of geometric thought enhance students’ conceptual understanding, offering a promising digital tool for mathematics instruction in technology-enhanced classrooms.