Being overweight in adolescence is an influential factor that determines obesity and overweight in adulthood, and there is a direct relationship between obesity in childhood, adolescence, and adulthood. Therefore, the present study aimed to investigate the prevalence of obesity and overweight and its related factors in male and female secondary school students of Bojnord City.

This descriptive study was conducted on 744 male and female secondary school students of Bojnord City by cluster sampling. The weight and height of the samples were measured, and their body mass index was calculated using standard guidelines. Other information was collected by a researcher-made questionnaire and a physical activity questionnaire for each of the examined samples, and the data was analyzed by Mann-Whitney and Chi-square statistical tests.

The results of this study showed that the prevalence of underweight was significantly higher among girls (P < 0.001) and the prevalence of overweight was significantly higher among boys (P = 0.013). Also, there was no significant difference between the prevalence of obesity in boys and girls (P = 0.085).

Considering the results of the prevalence of obesity, overweight, and underweight in Bojnord students and the lack of awareness among students about complications related to obesity and overweight, the implementation of intervention programs to prevent High-risk behaviors of obesity and overweight in students seems necessary.