Purpose: The purpose of this study was to investigate the factors affecting willingness of patient participation in ROK military hospitals. Methods: The study design was a descriptive correlational study. 133 patients participated in the study. Data were collected on patient safety knowledge, health-related self-efficacy, patient-provider relationship, and willingness to participate in patient safety using an internet survey. Data were analyzed with descriptive statistics and multiple regression using SPSS. Results: The patient's willingness to participate was 3.63, and the factors affecting the patient’s willingness to participate were health-related self-efficacy and patient-provider relationship. When medical staff encouraged patient’s participation, the mean score of the patient's willingness to participate was 3.69, and the factors affecting the patient’s willingness to participate were patient safety knowledge and patient-provider relationship. Conclusion: Building a good patient-provider relationship, enhancing patient education, and improving self-efficacy should be recommended to facilitate patient participation activities. Strategies to increase the opportunities for patient provider interaction, develop educational materials suitable for military hospital inpatients, and develop self-efficacy enhancement programs are suggested.