Purpose: The purpose of this study was to examine the relationship between sleep quality and stress among nursing students. Methods: A cross-sectional study was conducted with 94 nursing students from a University in Seoul. Participants completed questionnaires and the data were analyzed using t-test, ANOVA, and Pearson correlation coefficients. Results: The mean score of sleep quality was 6.93±2.66 among nursing students and 81.9% had a sleep problem. The mean score of stress was 18.61±4.84. Sleep quality was significantly different by clinical practice days per week, subjective physical health status, and subjective mental health status. Stress levels were significantly different by subjective physical health status, subjective mental health status, social relationship satisfaction, and satisfaction levels of nursing major and university. A significant relationship between sleep quality and stress (r=.45, p<.001) was found, meaning that a lower quality of sleep was significantly correlated with higher stress level. Conclusion: The results indicated that most nursing students had sleep problems and stress. Therefore, interventions are needed to be developed to lower the level of stress and increase the quality of sleep among nursing students.