Introduction and aim. Obesity is the leading one among the most common nutritional disorders seen during childhood period. We aimed to determine the incidence of obesity, obesity awareness, physical activity and associated factors in school-age children. Material and methods. The sampling was composed of 725 students who were studying in secondary schools during the 2016–2017 academic year. Data were collected with “Personel Information Form”, “Obesity Awareness Scale” and “Physical Activity Questionnaire for Older Children”. The mean age was 12.30±1.32 (10–15), 53% of the students were females and 60.1% of students have a person with obesity in the family. Results. We determined that 18.3% of the students were with obesity. The body mass index of students who have a balanced diet compared to those who have not is statistically significantly lower (p<0.05). There was a significant relationship between students’ body mass index and obesity awareness (r=-0.084, p=0.024). Conclusion. Screening for obesity and related factors, such as obesity awareness, having a balanced diet should begin in school-aged children for childhood obesity prevention.