Attending University is when many students first experience living away from home and learning the skills to manage their daily routines. Certain students tend to stay up late or reduce their length of sleep to have more time to study hard or to experience their lives. Nevertheless, irregular sleep patterns can harm the brain’s ability to learn and remember, resulting in lower academic performance among college students. Several studies have reported that poor sleep is associated with poor academic performance. However, most of these studies rely on subjective parameters, such as the Pittsburgh Sleep Quality Index (PSQI), to estimate sleep quality. These data may be influenced by subjective bias and are unable to quantify day-by-day variation in sleep. In this study, 33 undergraduate students who attended the Sleep Physiology class at National Cheng Kung University, Taiwan were invited to conduct a 14-consecutive day of sleep measurement using the actiwatch to estimate the objective sleep efficiency (SE). To quantify the irregularity of students’ sleep, the mean absolute deviation (MAD) values of the SE were considered. The experimental results show that SE has a significant positive correlation with the final exam scores. In addition, MAD of SE have a significant negative correlation with the final exam scores. This study provides objective and quantitative evidence that good and regular sleep is associated with better academic performance in college students.