<![CDATA[The implementation of differentiated learning in Indonesia's Merdeka Curriculum requires instructional resources that accommodate students' diverse learning readiness. However, Geography instruction in senior high schools continues to rely on uniform learning materials that provide limited opportunities for personalized learning. This study aimed to develop and evaluate a Readiness-Based Adaptive E-Module for Grade X Geography to enhance students' learning outcomes. The study employed a Research and Development (R&D) approach using the ADDIE instructional design model. The developed e-module integrates diagnostic readiness assessment, adaptive learning pathways, interactive multimedia, personalized feedback, and differentiated enrichment activities. The product was validated by subject matter, instructional design, and educational media experts before being implemented with 72 Grade X students at SMA Negeri 14 Medan. Product practicality was evaluated through teachers' and students' responses, while effectiveness was examined using a quasi-experimental pretest–posttest control group design, Independent Samples t-test, and normalized gain (N-Gain). The results indicated that the e-module achieved very high validity (94.46%) and very high practicality (93.04%). Students in the experimental group demonstrated significantly higher learning outcomes than those in the control group (p < .001), with a high N-Gain score (0.73). These findings indicate that the readiness-based adaptive e-module is a valid, practical, and effective instructional innovation for supporting differentiated Geography learning and personalized digital instruction in secondary education.]]>
