The study explored the effectiveness of e-books in teaching Mathematics to improve students’ academic achievement. Kotobee author and kotobee reader were used in the conduct of the study in one of the secondary schools in the Division of Cagayan de Oro City. The study used a one-group pretest-posttest design, involving quantitative and qualitative analyses. The kotobee author and reader, achievement test, and interviews were employed. Findings indicated that students achieved a satisfactory level when exposed to the interactive e-book. There was a statistically significant difference in how well students did on their tests before and after. Students are motivated to learn when using an interactive e-book to enhance their knowledge. Students had a remarkable learning experience with the interactive e-book.