This study aimed to evaluate the relationship among dental students' attendance at class lectures, use of online lecture materials, and performance in didactic courses. The study was conducted with second-year predoctoral students at Tufts University School of Dental Medicine during the fall semester of 2014. Three basic science and three preclinical dental courses were selected for evaluation. Online usage for each participant was collected, and a survey with questions about attendance and online behavior was conducted. The final grade for each participant in each selected course was obtained and matched with his or her online usage and attendance. Out of a total 190 students, 146 (77%) participated. The results showed no significant relationship between students' grades and their class attendance or online usage except for a weak negative relationship between class attendance and online usage for the Epidemiology course (p<0.001) and the overall preclinical dental courses (p=0.03). Although the results did not show strong relationships among class attendance, online usage, and course grades, most of the students reported that having the online resources in addition to the lectures was helpful.