Purpose: In an evolving clinical environment, nursing students face ethical dilemmas that require robust ethical decisionmaking and heightened sensitivity. Developing these competencies before clinical practice is crucial for effective patient care and professionalism. Therefore this study aimed to investigate the impact of ethical decision-making confidence and nursing professionalism on the ethical sensitivity of nursing students before clinical practice. Methods: Total of 121 third-year undergraduate nursing students from a university in D city who had not yet begun clinical practice participated in this study. Data were collected through an online survey, and analysis was conducted using the SPSS 23.0 statistical program, including descriptive statistics, t-tests, Pearson’s correlation coefficients, and multiple regression analysis. Results: Results indicated that ethical sensitivity was positively correlated with both ethical decision-making confidence (r=.59, p<.001) and nursing professionalism (r=.94, p<.001). Multiple regression analysis revealed that ethical decision-making confidence (ß=.15, p<.001) and nursing professionalism (ß=.86, p<.001) were significant predictors, accounting for 88.9% of the variance in ethical sensitivity. Conclusion: The findings underscore the importance of fostering ethical decision-making confidence and a strong sense of nursing professionalism in educational programs. Enhancing these aspects may improve nursing students’ ethical sensitivity, preparing them for ethical challenges in clinical practice.