Sleep is very important for human health. The consequences of sleep manifest themselves on both health and performance. The relationships between sleep and performance have been studied in many different fields, including humanities, medicine, psychology, education, business, etc. Sleep-related variables, such as sleep deprivation, sleep quality, and sleep habits, have been shown to influence sleep performance. students (Lack, 1986; Mulgrew et al., 2007; National Sleep Foundation, 2008; Pilcher & Huffcutt, 1996; Rosekind et al., 2010). According to Weitzman et al. (1981), delayed sleep phase syndrome (DSPS) was defined in three broad categories: long sleep latency on weekdays (normally falling asleep between 2 and 6 am), normal sleep duration on weekends week (usually sleep late and wake up late on weekends); and difficulty staying asleep. These sleep problems are common and present in students around the world. Results indicate that in the United States, 11.5% of college students experienced DSPS (Brown, Soper, & Buboltz, 2001). Not only that, Australian studies have found that the prevalence of DSPS in students (17%) is higher than in adults (6-7%) (Lack, 1986; Lack, Miller, & Turner, 1988). DSPS-related studies have also been conducted in other countries such as Japan, Norway, and Taiwan (Hazama, Inoue, Kojima, Ueta, & Nakagome, 2008; Schrader, Bovim, & Sand, 1993; Yang, Wu, Hsieh, Liu, & Lu, 2003 ). Furthermore, in Lack's (1986) study, the DSPS group experienced weekday sleepiness more often than the non-DSPS group. Additionally, members of the DSPS group were found to perform lower academically than the non-DSPS group when course grades were examined. In a more recent article...... center of article...... AT, Omvik S, Pallesen S, Bjorvatn B, Thayer J, Nordhus H. Qureshi AU, Ali AS, Hafeez A, Ahmed TM ). Furthermore, the study showed that students who obtained good grades (A, B) were those who slept for more than 7 hours, but those who failed most of the exams were mainly those who slept less. However, a similar study conducted in the United States showed that students who had struggling grades (C, D, F) were the ones who got significantly less sleep than those who got A and B grades (Wolfson AR, Carskadon MA). According to the study, students slept on average only 4.74 hours before the exam, and females slept less (4.71+1.82 hours) than males (4.77+3.27 hours). This finding was similar to a cross-sectional study conducted in São Paulo, which showed that kids slept about 390 minutes. However, their academic performance was not affected by the sleep cycle disorder.