Usability test method was used for the research. A course on Coursera called `Effective Speaking` is selected for the research to conduct usability test. Nine authentic tasks were determined by the researchers to determine usability problems of Coursera. Following this, data of task completion success and task completion duration were collected by a screen recorder during performances considering ISO 9241-11 standards. In addition to this, three open ended questions were asked to the participants in order to get their ideas about usability problems of the system and possible solutions for those problems. Lastly, Tobii T120 which is a desktop eye tracking device was used to collect eye tracking data from three participants to validate preliminary findings. One of the research finding shows that an office worker rarely focused on search bar, which has an important role to find courses. Therefore, it is recommended that Coursera system should change the design of search bar so that online learners can easily find what they look for. Additionally, one of the participants took too much time for unenrolling from the course. Eye tracking findings indicate that unenrolling from the course on Coursera is presented as a three dot menu, which has not any affordance as the user did not gaze the menu. Furthering this, the participants said that coursera system does not provide good enough language support. In other words, the participants selected Turkish as the system language during taking the course but Coursera did not completely turn into Turkish because most part of the system were still in English. Overall, Coursera system has a good design for usability considering research findings but some usability issues such as complication of finding a course on search bar, inadequate design of unenrolling from any course and lack of language support could be addressed to improve usability of Coursera.