This study develops and evaluates a digital textbook on plant transpiration for high school biology students in Timor-Leste. Using Apple’s Pages application, the textbook integrates multimedia elements such as videos, interactive images, and quizzes. The experimental design involved 60 grade XI science students, divided into an experimental group using the digital textbook and a control group using a traditional printed textbook. Learning outcomes were assessed through pre- and post-tests, along with a student satisfaction survey and teacher feedback. Results indicate a statistically significant improvement in academic achievement for students using the digital textbook, with a mean post-test score of 7.30 compared to 6.10 in the control group (p < 0.05). Student satisfaction was high, with a mean rating of 4.8 for multimedia content. Teacher feedback highlighted the textbook’s interactive features as beneficial for student engagement and comprehension. These findings suggest that digital textbooks effectively enhance learning outcomes and motivation in an educational context for high school biology.