Purpose: The aim of this study was to determine the perceived needs and confidence of school nurses in health education at middle and high schools in Seoul, Korea. Methods: A descriptive survey questionnaire was developed by a research team to investigate the perceived needs and confidence across eight health education areas. A total of 329 school nurses at secondary schools in the metropolitan areas of Seoul participated. Descriptive statistics, the t-test, and ANOVA were conducted to analyze the data. Results: Generally high means in perceived education needs(Mean: 3.8~4.7/5) and health education confidence (Mean 3.3~4.5/5) were reported. However, there were significantly low means of health education confidence related to perceived needs in health education for all areas of health education. While injury prevention and emergency care education were the highest perceived educational needs and were also areas with high confidence of school nurses, mental health, social health, and sexual health were areas where nurses showed a significantly lower confidence. In general, nurses with a longer clinical experience and educational career had a higher confidence in injury prevention, emergency care, and mental health. Conclusions: Multi-level support, including the continuing education and proactive in-service training, for the school nurses needs to be developed to improve their teaching competency.