To evaluate the prevalence of scoliosis and the risk factors in elementary school students.A cross-sectional study was carried out in 954 students in 2015. The instrument involved was a questionnaire on postural habits, socioeconomic conditions, and demographic factors. The anthropometric measurements, including height and weight, a visual inspection of the deformity of the vertebral column, the leveling of shoulders, and the Adam's test were obtained. The sample was calculated in the expected frequency of 12.3%, acceptable error rate of 2.0% and confidence level of 95.0%. To compare the proportions, the chi-square test or Fisher's exact test was applied. The association between scoliosis and risk factors was evaluated by logistic regression, being significant p <0.05.The prevalence of scoliosis was 24.3%, higher in obese patients and students who adopted a sitting position for a long period of time. Obese students showed a 1.8 times higher chance of testing positive Adam's Forward Bend Test when compared to normal-weight/lean and 2.1 times higher chance compared to overweight students. The sitting position for watching television increases the chance of testing positive Adam's test in 38.0%, when compared to the lying position. Obesity increases the risk of testing positive Adam's test in 74.0 and 98.0%, when compared, respectively, to the underweight/normal weight and overweight.There was a high prevalence of scoliosis in students from public elementary schools in Santos. The most influential factors for this deviation of the spine were obesity and the position adopted by students to watch television.