Purpose: This study aimed to identify factors affecting nursing students' professional self-concept. Methods: A survey was conducted from August to October 2022, targeting 110 students in the 3rd and 4th grades at three universities. Data were analyzed using descriptive statistics, t-tests, ANOVA, Pearson's correlation, and multiple linear regression. Results: There were significant differences in professional self-concept according to application motivation (F=5.43, p=.006), school record (F=3.24, p=.043), major satisfaction (t=-6.38, p<.001), desired occupation (F=9.30, p<.001), participant health status (F=4.31, p=.016), character (F=25.29, p<.001), clinical practice satisfaction (t=-5.36, p<.001), and change of thinking about career path after clinical practice (t=2.78, p=.006). Professional self-concept showed significant correlations with clinical practice stress (r=-0.37, p<.001) and resilience (r=0.66, p<.001). The variables affecting nursing students' professional self-concept were resilience (β=.38, p<.001), character (β=.32, p<.001), major satisfaction (β=.28, p<.001), and clinical practice stress (β=-.18, p=.007); the explanatory power was 65%. Conclusion: A professional self-concept enhancement program should be developed to promote the establishment of a positive professional self-concept in nursing students. As a strategy, it should reflect individual personality tendencies, improve major satisfaction and resilience, and reduce clinical practice stress.