This research aims to determine the cognitive structures of secondary school students about COVID-19. In this research, a case study, one of the qualitative research methods, was used, and demographic information and a word association test were the data sources. The study group of the research consists of 226 students who continue their education in the 6th and 7th grades of a public secondary school. The data were collected via Google Form, and the obtained data were analyzed by content analysis. The cognitive structures of secondary school students on the concept of COVID-19 are grouped under 11 categories. These categories are COVID-19 Prevention Methods, COVID-19 Reflections in Press, COVID-19 Results, COVID-19 Perceptions, Causes of COVID-19 Transmission, COVID-19 Treatment, COVID-19 Symptoms, Countries where COVID-19 are Common, Characteristics of COVID-19, COVID-19 Carriers and COVID-19 Diagnostic Ways. When these categories were examined, it was seen that the students' cognitive structures about the concept of COVID-19 focused on COVID-19 Prevention Methods, COVID-19 Reflections in Press, COVID-19 Results, and COVID-19 Perceptions. In addition, it has been determined that some students have misconceptions about the COVID-19 virus.