Abstract In the post-pandemic world, open educational resources (OER) have the potential to ensure educational equity by providing all students with access to learning materials and by supporting teachers’ instructional practices through readily available, adaptable resources. However, the quality of OER continues to be a concern. Therefore, this study explored the use of (1) GeoGebra and scaffolding strategies to develop OER for secondary school mathematics teaching and (2) formative evaluation techniques to enhance the quality of the OER. A GeoGebra expert and a total of 40 frontline teachers participated in three review cycles of the OER development in the project. The feedback from each cycle informed the application of scaffolding strategies in the development of OER for the subsequent cycles. In Cycles 2 and 3, teachers rated the OER and provided feedback through surveys for further improvement. The results indicated that teacher ratings were significantly higher in Cycle 3 (n = 40, Mdn = 5) than in the previous cycle (n = 21, Mdn = 4) regarding the appropriateness of the OER for students with different learning preferences, z = − 2.87, p