The COVID-19 pandemic has resulted in most universities engaging in emergency online learning which they were not adequately prepared for. The emergency nature of the learning process raises questions on how students are able to effectively engage in the process. This study explored undergraduate students from the Department of Teacher Education, University of Ghana's knowledge, usage, and challenges of using online learning platforms during the 2019/2020 second semester academic year. The students had to complete all courses online in the middle of the semester because of the pandemic. Five hundred and thirty-eight (538) students participated in the study; a survey was used to collect data from the students. Descriptive statistics (percentages and frequencies) and inferential statistics (t-test) were used to analyse the data. The results show that not all students who took part in the online learning knew about online learning platforms, indicating that students were not given the needed training before all courses were migrated to be taught online. Almost half (45%) of the students were not engaged in online platforms for learning before COVID-19 indicating engaging in online learning was a very new experience for many of the students. As a result, some students were not able to use and engage in the online platforms and a lot of them indicated they were not comfortable learning online. Access to internet data (61%), stable electricity (54%), technological equipment (47%), internet connectivity problems (77%) and geographical location (47%) did not allow some students to participate well in the online learning.