Background: Sleep is an essential physiological function in which both the body and the mind rest. However, lack of sleep and deprivation can greatly affect many aspects of our lives including social, academic, psychological, and even physiological factors. Medical students often tend to have long studying hours and less sleep throughout their college time. We aim to study the effect of sleeplessness and deprivation among them. Methods: This is a cross-sectional study that was performed during the 2017-2018 academic year at the College of Medicine of King Saud University in Riyadh, Saudi Arabia. We included a stratified random sampling technique where 430 healthy medical students from five academic years (first, second, third, fourth, and fifth years) of both genders were recruited to fill a self-administered questionnaire to assess sleep disorders. The questionnaire included questions exploring the impact on social life and academic performance by grade point average (GPA) 5/5. Data were analyzed using IBM SPSS V 21.0 software. Results: Out of 430 participants, main causes of sleep deprivation were stress 296 (19.6%), college assignments 310 (20.6%), internet 257 (17.0%), anxiety 157 (10.4%), work 107 (7.1%), socializing with friends 99 (6.6%), depression 78 (5.2%), family commitments 70 (4.6%), video games 55 (3.6%), sleep disorder 41 (2.7%), partying 17 (1.1%), loud disruptive housemates 12 (0.8%) and young children 9 (0.6%). Meanwhile, gender (P < 0.01), academic performance (P < 0.01) and academic level (P = 0.005) had significant association with sleep deprivation. Conclusion: The results showed that the medical students at King Saud University are suffering from sleep deprivation and the main reason for their sleep deprivation is the academic burden. Therefore, sleep deprivation impacts their academic performance.