Background Ethics education can be developed in undergraduate nursing curriculum using a variety of teaching and learning strategies, and the content of narrative-based stories has rarely been evaluated in ethics courses. Objective This study aimed to compare the effect of teaching ethical principles through narrative ethics and lectures on the moral sensitivity of undergraduate nursing students. Methods This was a pretest and posttest quasi-experimental study with a control group. A total of 105 undergraduate nursing students from the nursing department of (...) Kerman University of medical science were included in the study. The narrative-based story and lecture lasted for four two-hour sessions. The outcomes were measured by a moral sensitivity questionnaire. Results The study results showed that teaching ethical principles had a significant effect on the mean score of moral sensitivity in the intervention groups after the intervention, but it was not significant in the control group. Based on the mean score of moral sensitivity, the students in the narrative story group got a higher score in all subscales of moral sensitivity questionnaire. Conclusion Based on this study’s findings, it can be concluded that narrative-based education is an effective way for undergraduate nursing students to promote their moral sensitivity and the ability to make ethical decisions. (shrink)