The paper describes a study on the relationship between students' online quiz taking behavior and their performance. Unsupervised online quizzes have been used widely by higher learning institutions as an activity in a blended learning model and found to be a valuable formative assessment tool for students to self-assess their learning more flexibly and conveniently than taking the quizzes in the classroom. Past studies also suggested that online quizzes could engage students in learning more effectively and increase students' motivation to learn more than inclassroom quizzes. Although the online quizzes offered positive effects on students' learning, limited studies were conducted to understand students' behaviors in taking unsupervised online quizzes and how they affect their performance. Therefore, this study aims to investigate how students' online quiz taking behavior affects their performance. Four types of ordinary online quiz taking behavior, namely (1) access to printed references, (2) access to digital references, (3) peer discussion, and (4) test preparation practices are included in the study. The students' online quiz taking behavior was obtained using a self-rated post-task questionnaire, while the performance data of the students were taken from their scores in three unsupervised online quizzes for a Computer Organization course, as a compulsory course for students enrolling in an Information Technology bachelor's degree program. The results of the study suggested that students who frequently access to printed references, access to digital references, and have peer discussion during online quiz taking obtained higher marks for the online quizzes compared to the students who never or seldom do so. A similar result also found among students who prepared or did revision before taking the quizzes. Further, students who obtained higher marks in the online quizzes tend to refer to digital references (i.e., softcopy of the lecture notes, and search from the Internet) more frequently than the students who obtained lower marks. The findings of the study suggested that preparation and revision before the quizzes are essential, although there are resources available to refer to while taking the unsupervised online quizzes.