OBJECTIVES: This study examined the impact of nurses' critical thinking disposition, clinical reasoning competency, and nursing practice environment on their medication safety competency. METHODS: A cross-sectional design was employed, involving a convenience sample of 210 nurses from four tertiary general hospitals and two general hospitals. Data were collected in September 2023 utilizing structured online self-report questionnaires and analyzed utilizing descriptive statistics, independent RESULTS: Significant positive relationships ( CONCLUSIONS: These findings highlight key factors influencing medication safety competence of nurses and underscore the need for targeted strategies to enhance patient safety by optimizing critical thinking, clinical reasoning, and the nursing practice environment in healthcare settings.