A balanced diet is crucial for the growth and development of school-age children and adolescents who receive most of their nutrients at school. This study aimed to analyze big data on school meal service information nationwide to evaluate whether the nutritional needs and students' preferences are considered while providing meals and to supply data for future school meal planning. Lunch menu data was collected from the National Education Information System Open Educational Information Portal, and Python 3.12 was used for text mining and frequency analysis. In addition, the difference in distribution by food group was tested using SPSS, and the annual percent change of each menu item was evaluated using SAS. An analysis of menus frequently provided for school meals showed that curried rice, banquet noodles, beef and seaweed guk were served most often in elementary schools. In middle/high schools, banquet noodles, curried rice, fresh cabbage kimchi were the most common. The comparison of food group distribution showed significant differences in both elementary and middle/high schools (P<0.001). The types of frequently served menus remained at similar levels over the years, but the rankings changed. Specifically, both elementary and middle/high schools appeared to adopt a diet reflecting students' preferences, as the annual provision for foods such as Rosé tteokbokki showed a sharp rise. This study is meaningful as it analyzes school meals nationwide by generating information that may help formulate and implement strategies to increase students' school lunch intake in the future using big data.