Online education is common in the current digital world. There has been some progress in adopting synchronous online education in the higher education sector, using general purpose online meeting software. The current global trend is to adopt human-technology integration to achieve better classroom engagement with the help of blending learning and to achieve equal or better performance than physical learning. In this paper, we investigate the research question “What are the key factors that affect the perceived quality ratings of online university classrooms?” To find the answers, using expert and convenience sampling methods, we perform web-based online quantitative cross-sectional surveys on university teachers and students. We use correlation analysis and decision trees as educational data mining methods to analyse and explain the collected data. Our findings from this investigation are that having appropriate online tools, having interactions in online classes, getting math lessons and labs well, and lively and engaging teaching methods are important for students. For teachers, getting participation, interaction, and feedback from students are key to improve online classes. Our study also seeks a hierarchical explanation behind the relations between the perceived quality ratings and the identified factors. Our findings would help higher education researchers in redesigning future online classrooms.