This study aimed to develop an interactive e-book assisted by the AnyFlip application on the topic of flat-sided geometric solids for junior high school students. The study employed the Research and Development (R&D) method using the 4-D development model, implemented up to the develop stage. The product focused on the processes of designing, creating, validating, and refining learning media to ensure its feasibility for classroom use. The developed product was an interactive e-book combining text, images, learning videos, and practice exercises to create a more engaging and understandable learning process. The research subjects consisted of media experts, material experts, and 25 eighth-grade students of SMP YP HKBP Pematangsiantar. Data were collected using validation sheets and student response questionnaires with a Likert scale. The validation result from media experts obtained a percentage of 87.89%, categorized as valid, while the material expert validation obtained 86.25%, also categorized as valid. The product trial conducted with students obtained a percentage of 79.6%, categorized as effective. The e-book also integrated an ethnomathematics approach through examples of geometric solids related to local culture, making learning more contextual and engaging. Based on the results, the interactive e-book assisted by the AnyFlip application was declared feasible and effective as a mathematics learning medium on the topic of flat-sided geometric solids. The student trials showed positive responses and helped students become more interested in and better understand the learning material.