Purpose: This study examined the influence of nurses' communication competency, critical thinking disposition, and perception of patient safety culture on patient safety competency in armed forces hospitals. Methods: A crosssectional design was employed with a convenience sample of 204 nurse officers from four armed forces hospitals in South Korea. Data were collected through a self-administered questionnaire from August 10~23, 2019, and analyzed using descriptive statistics, t-test, ANOVA, Pearson’s correlation coefficients, and multiple regression. All analyses were conducted using SPSS for Windows 21.0. Results: Patient safety competency scores were 4.35±0.40 for patient safety attitudes, 3.63±0.64 for patient safety knowledge, and 3.94±0.51 for patient safety skill. Communication competency, critical thinking disposition, and perception of patient safety culture were positively correlated with patient safety competency. Communication competency (β=.30, p=.002) and perception of patient safety culture (β=.24, p=.001) were identified as particularly important factors influencing patient safety competency. Conclusion This study’s results suggest that education programs to enhance communication competency and patient safety culture could increase patient safety competency among nurses in armed forces hospitals.