The COVID-19 pandemic has forced the education sector to switch to online learning. To make the transition a success, there is a need to understand students' perception towards online learning and design a learning experience around it. Thus, the aim of this paper is to identify students' perceptions towards online learning in terms of motivation, task engagement and acceptance. The systematic literature review method was used to search for relevant papers and synthesize the findings. 40 articles from the year 2020 obtained from Google Scholar. It is found that the most used method in studying students' perception is the quantitative method and students' acceptance was the most discussed topic. It is also found that the primary factors influencing motivation and acceptance are sense of ownership and accessibility respectively. In terms of task engagement, only half of the findings reveal that students are engaged in online learning. In summary, the three main constructs are important items that should be taken into consideration when teaching an online course to ensure the success of the course. Through this systematic review, future research can identify and explore different areas and perspectives on this topic.