This study investigates the factors influencing students' engagement in sustainable online education, particularly in the context of the COVID-19 pandemic. Using a mixed-methods approach, the research collected data from 452 university students through a structured questionnaire. The CHAID decision tree algorithm was applied to identify the key predictors of student engagement. The findings reveal that the quality of course content is a significant cognitive predictor, with 61.7% of students showing high engagement due to high-quality faculty content. Social presence, such as having a designated private space and requiring webcam use, also plays a crucial role in enhancing student engagement. Teaching presence, including interactive classrooms and rapid feedback from teachers, further contributes to increased student engagement. The study emphasizes the importance of high-quality content, interactive learning environments, and timely feedback in optimizing student engagement and the sustainability of online education. The research provides practical insights for educators and institutions to improve their online educational offerings and foster a more engaging and effective learning experience.This study investigates the factors influencing students' engagement in sustainable online education, particularly in the context of the COVID-19 pandemic. Using a mixed-methods approach, the research collected data from 452 university students through a structured questionnaire. The CHAID decision tree algorithm was applied to identify the key predictors of student engagement. The findings reveal that the quality of course content is a significant cognitive predictor, with 61.7% of students showing high engagement due to high-quality faculty content. Social presence, such as having a designated private space and requiring webcam use, also plays a crucial role in enhancing student engagement. Teaching presence, including interactive classrooms and rapid feedback from teachers, further contributes to increased student engagement. The study emphasizes the importance of high-quality content, interactive learning environments, and timely feedback in optimizing student engagement and the sustainability of online education. The research provides practical insights for educators and institutions to improve their online educational offerings and foster a more engaging and effective learning experience.