OBJECTIVES: To determine the opinions of nursing students about the causes of obesity in school-aged children. STUDY DESIGN: Cross-sectional study. PARTICIPANTS AND METHODS: First and second year nursing students of the Nursing Graduate Study of Josip Juraj Strossmayer University in Osijek participated in the research. The research was conducted using a self-structured questionnaire. The answers to the questions were evaluated according to the Likert scale. The statistical program IBM SPSS Statistics 26.0 was used for statistical data processing. for Windows, version 0.0.1., IBM, USA, Software inc; in 2021 RESULTS: Total of 101 respondents participated in the research on the causes of obesity in school-age children among nursing students, of which 85% were women and 15% were men aged 25 to 48. As for the opinion on the factors for the development of obesity in school-age children, the mean values of the ratings ranged from 3.2 to 4.2 out of a possible 5 depending on the factor. Most respondents agree (ratings 4 and 5) that cultural factors influence obesity are married. Most young people between 25-30 and 36-40 fully agree that frequent consumption of "fast" food has a harmful effect on the obesity of young generations. CONCLUSION: Although obesity among school children is on the rise and represents a growing public health problem, and nurses have an important role in its prevention, there is concern about the lack of research in this field. This research sought to examine the opinions and knowledge of nursing students, however, research is needed in which school medicine nurses will participate at the national level in order to examine the level of knowledge and educate nurses about prevention measures.