Background: Moral courage, as a strategy to reinforce ethics and doing courageous deeds, is essential in providing nursing cares. Proper management of ethical challenges, professional commitment to patients, and ethical performance require moral courage. In addition, this concept is affected by personal and professional traits and organizational cultural. Ethical climate is a part of organization character, represents ethics in the organization. Ethical climate helps individuals to assess the problems and also acts as a guide for making decision about acceptable and unacceptable behaviors. The present study is an attempt to examine some of the predicting variables of moral courage in nurses. Methods: The study was carried out as predictive study in 2019. The subjects were 267 nurses working in hospitals who were selected through simple random sampling. Data gathering tool included a demographics form, Sekerka’s job satisfaction standardized questionnaire, and Elson’s ethical climate standardized questionnaire. Results: The mean scores of moral courage and ethical climate in nurses were 87.07±15.52 and 96.12±17.17 respectively. The findings showed that 16% of moral courage score in nurses was attributed to ethical climate and overtime work hours per month. Conclusions: Although, ethical climate and overtime work hours were the main factors in moral courage, not a notable percentage of the variance of moral courage was attributed to them. Therefore, there is a need to determine other factors in moral courage.