Background The global COVID-19 pandemic has challenged nurse leaders in ways that one could not imagine. Along with ongoing priorities of providing high quality, cost-effective and safe care, nurse leaders are also committed to promote an ethical climate that support nurses’ moral courage for sustaining excellence in patient and family care. Aim This study is directed to develop a structure equation model of crisis, ethical leadership and nurses’ moral courage: mediating effect of ethical climate during COVID-19. Ethical consideration Approval was (...) obtained from Ethics Committee at Faculty of Nursing, Alexandria University, Egypt. Methods A cross-sectional design was used to conduct this study using validated scales to measure the study variables. It was conducted in all units of two isolated hospitals in Damanhur, Egypt. A convenient sample of 235 nurses was recruited to be involved in this study. Results This study revealed that nurses perceived a moderate mean percent (55.49 ± 3.46) of overall crisis leadership, high mean percent (74.69 ± 6.15) of overall ethical leadership, high mean percent (72.09 ± 7.73) of their moral courage, and moderate mean percent of overall ethical climate (65.67 ± 12.04). Additionally, this study declared a strong positive statistical significant correlation between all study variables and indicated that the independent variable (crisis and ethical leadership) can predict a 0.96, 0.6, respectively, increasing in the dependent variable (nurses’ moral courage) through the mediating impact of ethical climate. Conclusion Nursing administrators should be conscious of the importance of crisis, ethical leadership competencies and the role of ethical climate to enhance nurses’ moral courage especially during pandemic. Therefore, these findings have significant contributions that support healthcare organizations to develop strategies that provide a supportive ethical climate. Develop ethical and crisis leadership competencies in order to improve nurses' moral courage by holding meetings, workshops, and allowing open dialogue with nurses to assess their moral courage. (shrink)