We explored the barriers to reporting patient safety incidents experienced by nurses and resident physicians while working in tertiary hospitals in South Korea. Sixteen in-depth interviews with 10 nurses and 6 resident physicians, all of whom had experienced patient safety incidents, were conducted. The interviews were analyzed using directed content analysis in accordance with a coding scheme developed in this study, which contains 4 categories (incidents and reporters, reporting procedures and systems, feedbacks, and reporting culture) and 9 subcategories. The barriers to reporting near-misses included the following: characteristics of the incident (eg, nonhazardous and high frequency), reporters' lack of knowledge, uncertainty, fear of blame, lack of role model, and inappropriate responses. Reporting adverse/sentinel events was also prevented by feelings of pressure or guilt, the fact that reporting was nonmandatory, and a belief that reporting was not part of the job. Some other barriers included lack of education, review process after reporting, lack of confidentiality when reporting, absence of feedback for reporting, unfair reporting based on work experience, perception of potential blame, and stigmatization resulting from it. In South Korea, a national system for reporting and learning of patient safety accidents has been operating since July 2016. To fully implement this system, it is necessary to encourage reporting at the institutional level. Our results might help reduce the barriers to patient safety incident reporting among nurses and resident physicians in tertiary hospitals in Korea through informing the development of improvement plans.