In recent years, e-textbooks have become increasingly popular in several countries. E-textbooks contain many visual elements, such as images, charts, tables, and text. This study aimed to explore the impact of design elements in e-textbooks on the visual behavoiur of school students based on their grades and gender, given that the use of e-textbooks may vary among different grade levels and genders. Data were collected from 91 tenth-(15 years old) and eleventh-grade (16 years old) students, including 46 males and 45 females. An eye-tracker device was used to record the visual behaviour of participants while interacting with the e-textbook. This study provided mean and standard deviation values for various eye-tracking metrics, including average visit duration, time to first fixation, fixation count, and average fixation duration. The findings revealed that Grade 11th students exhibited slightly higher values for various eye-tracking metrics when compared to their Grade 10th counterparts. Notably, females exhibited a slightly higher average visit duration than their male counterparts did. In contrast, males demonstrated a marginally longer average fixation duration. However, the most striking gender-related differences were observed in the fixation count mean and time to first fixation mean, where males exhibited significantly different values than females. The analysis revealed that visual components in e-textbooks can enhance students’ understanding and retention of information, and it is recommended that e-textbook developers and instructional designers use visual cues, relevant images, charts, graphs, and a well-organized layout to optimize design and layout for efficient learning. The design of e-textbooks has a significant impact on the visual behaviour of students in schools.