Most previous studies have focused mainly on the influence of external interventions (such as moral climate, moral education, and training) on students' moral sensitivity. However, few studies have explored the impact of self‑leadership on promoting moral sensitivity. Based on social cognitive theory, this study aimed to explore the relationship between self‑leadership and moral sensitivity among medical college students and compare the differences between medical students and nursing students. This study is a cross-sectional study. A total of 479 medical college students from China were investigated via self‑leadership scale and moral sensitivity scale. Pearson's correlation analysis, Structural Equation Modeling (SEM), and a group comparison test in Mplus 7.4 were conducted. The results showed that self‑leadership has a significant effect on moral sensitivity and major is a significant moderator in this relationship. Specifically, although medical students' moral sensitivity is greater than that of nursing students, the effect of self‑leadership on the moral sensitivity of nursing students is greater than on that of medical students. These results put forwards feasible opportunities for improving the moral sensitivity of medical students, which has important impacts on medical ethics education.