Purpose: This descriptive study investigated the effects of authentic leadership and coworker support on psychological well-being of staff nurses. Methods: The participants were 166 staff nurse working in university hospital located in D city. Data were collected from July 1 2017 to 31, 2017. Data analysis was performed using descriptive statistics, t-test, ANOVA, Pearson’s correlation coefficient, and hierarchical regression. Results: The regression model that included demographics and coworker support explained about 40.0% of psychological well-being. Marital status, nurse satisfaction, turnover experience, and coworker support were the predictors of psychological well-being in staff nurses. Conclusion: Coworker support was an important predictor of the psychological well-being of staff nurse. Therefore, strategics to improve coworker support are needed to increase psychological well-being in the clinical field.