Purpose: The purpose of this study was to identify sleep quality, job stress, symptoms of stress (SOS), and coping and to examine factors influencing sleep quality in clinical nurses. Methods: A cross-sectional study was conducted with 265 clinical nurses at three general hospitals. A self-administrated questionnaire was used for data collection, and data were analyzed using descriptive statistics. Pearson correlation coefficients, t-test, ANOVA, and backward multiple regression with the SAS statistical program. Results: Sleep quality showed significant differences according to the sociodemographic characteristics of age, length of work, education, current workplace, current job position, shift work, and marital status. Sleep quality was negatively associated with SOS and job stress. Significant factors influencing sleep quality of the clinical nurses were cognitive-behavioral SOS, physiological SOS, inappropriate rewards, physical work environment, and shift work. Conclusion: The findings indicate that cognitive-behavioral SOS, physiological SOS, job stress regarding inappropriate rewards and physical work environment, and shift work are useful to predict levels of sleep quality of clinical nurses. These factors should be considered when developing nursing interventions to improve sleep quality of clinical nurses through stress management.