This study aimed to develop a simulation-based scenario for pediatric nursing based on Kawasaki disease and to evaluate its impact on nursing students' knowledge, critical thinking disposition, self-efficacy, stress levels, and clinical performance. Methods: The scenario template was developed using the ADDIE model based on the National League for Nursing/Jeffries Simulation Framework. A quasi-experimental, single-group pretest-posttest was used. The study was conducted between March 3 and April 18, 2025, with 64 fourth-year nursing students. Self-report questionnaires were used to assess knowledge, critical thinking disposition, and selfefficacy. Stress was measured using physiological indicators, and clinical performance after the simulation was independently evaluated by both the instructor and researcher. Results: The scenario template required approximately six hours, and the simulation scenario operated for 20 minutes. Evaluation of the simulation`s effectiveness showed significant improvements in knowledge of Kawasaki disease (t=-6.96, p<.001), critical thinking disposition (t=-4.08, p<.001). The average clinical performance score was 64.81±6.61 out of a total of 86 points. Conclusion: The simulation-based learning method using the developed Kawasaki pediatric nursing scenario template was shown to be effective in enhancing clinical performance among nursing students. It may serve as a valuable educational tool for pediatric nursing education and future simulation-based training programs.