Background <p>Due to its geographic and climatic characteristics, Turkey faces a high risk of natural disasters such as earthquakes, floods, and landslides. Therefore, nurses must be competent in all phases of the disaster management cycle. However, the current state of nursing education in Turkey is inadequate, leaving students feeling unprepared and uncertain about their roles and responsibilities in disaster situations. Furthermore, no studies have evaluated the use of standardized patient simulations in disaster nursing in Turkey. The objective of the present study is to evaluate the effect of repeated standardized patient simulation-based disaster training on nursing students’ self-efficacy.</p> Methods <p>A quasi-experimental study was carried out with 44 fourth-year nursing students. The disaster nursing course includes theory and practice. Within the scope of the study, theoretical training and laboratory practices were carried out on obstetric evaluation and pregnancy follow-up in disasters, care practices after abortion, family planning counselling in disasters, sexual and reproductive health. After training, two repeated standardized patient simulations were conducted. Data were analyzed using SPSS version 25.0.</p> Results <p>The median score for disaster nursing practice skills increased among students as a result of repeated simulations, and significant differences were found between applications (<i>p</i> &lt; 0.001). Additionally, a significant difference was found in the median scores on the Disaster Response Self-Efficacy Scale before and after the first and repeated standardized patient simulations s(<i>p</i> &lt; 0.001).</p> Conclusions <p>Simulation-based education improved nursing students’ disaster nursing skills and increased their disaster response self-efficacy.</p> Clinical trial number <p>Not applicable.</p>