Purpose: The aim of the study is to determine daytime sleepiness in university students and its relationship with internet addiction as the determinant. Method: A descriptive cross-sectional design was used. Study population consisted of 1,150 first- and fourth-year students studying in some faculties at a university located in the Central Anatolia Region of Turkey. Findings: In this study, it was determined that the students obtained a mean score of 5.9 ± 2.1 points from the daytime sleepiness scale and the rate of those with daytime sleepiness problem was 17.9%. Furthermore, 52.3% of the students had a sleep duration of 7–8 hours. An increase in internet addiction mean score increases the risk of daytime sleepiness approximately one time. Conclusions: Increase of internet addiction score increases the risk of daytime sleepiness approximately one time.