Numerous studies over the years have documented an effect of human chronotypes on physiological and psychological processes. Studies evaluating the impact of an individual's chronotype on his/her academic achievement have indicated that morning chronotypes have an academic advantage over evening chronotypes. However, these studies did not account for the time of day in which the participants were being evaluated. The goal of the present study was to examine whether morning chronotypes do have an academic advantage over evening chronotypes when the time of day of classes and exams is taken into consideration. We obtained morningness-eveningness scores and course grades from 207 university students who took classes (and exams) at different times of the day. We confirmed that morning chronotypes attain better grades than evening chronotypes, although the association is weak (r = 0.02). The difference persisted even after the time of day of classes and exams was taken into consideration. This is probably due to the fact that evening chronotypes are generally more sleep deprived than morning chronotypes as a result of the early schedule of most schools, which can impair their performance both early and late in the day.