Aim: The aim of this study is to examine the effect of a mobile application, developed based on the Thompson \& Thompson bioethical decision-making model, on the ethical decision-making and ethical sensitivity of nursing students. Method: This randomized controlled trial, planned with pre-, post-, and followup tests, will be conducted at Necmettin Erbakan University Faculty of Nursing during the 2026-2027 academic year. The study population will consist of 4th-year students enrolled in the Necmettin Erbakan University Faculty of Nursing during the 2026-2027 academic year. The sample size was statistically calculated using the G Power 3.1.9.7 software package. The total sample size was calculated as 82. To prevent data loss, the sample size was increased by 10%, resulting in a sample size of 90 students. Students in the intervention group will use the mobile application. Students in the control group will conduct face-toface case analysis. The research data will be collected using the "Introductory Information Form", "Ethical Dilemma Test in Nursing" and "Adapted Ethical Sensitivity Scale for Nursing Students". The data will be analyzed using the IBM SPSS 22 software package. Conclusion: As a result of the research, it is predicted that the mobile application developed based on the Thompson \& Thompson bioethical decision-making model will have a positive effect on the ethical decision-making and sensitivity levels of nursing students.