Abstract: Background and Objective: Coffee is one of the most popular beverages in the world. Caffeine contained in coffee is a stimulant that acts on adenosine receptors to prevent sleepiness and promote alertness. In this study, we investigated the effect of coffee consumption on sleep quality of undergraduate students studying medicine. Materials and Methods: A cross-sectional study and convenient sampling method was used. A total of 350 students were enrolled and data were collected via a self-administered questionnaire based on the validated Pittsburgh Sleep Quality Index (PSQI) questionnaire. Results: The majority of students (73.1%) in this study consumed coffee, with instant coffee being the most preferred type. Coffee consumption was most frequent after 8 pm and the most common volume consumed daily was between 251 and 500 mL. The volume of coffee consumed daily was related to sleep quality. Conclusion: Although, coffee consumption had a non-significant impact on the quality of sleep among the total study population, we observed a large degree of intra-individual variability in the effects of caffeine.