Purpose: To assess the prevalence and severity of dental caries among 12-year-old schoolchildren and to examine its possible association with maternal schooling. Materials and methods: A cross-sectional study involving a representative sample (n = 253) of the 12-year-old schoolchildren enrolled in 14 schools of the municipality of Curitibanos, Brazil was carried out in 2006. Clinical information was obtained through the World Health Organization criteria. Non-clinical data were obtained through interviews with schoolchildren. Associations were analysed using chi-square test or Fisher exact test followed by non-conditional multiple logistic regression analysis to test the independence of associations between outcome and explanatory variables. P-values were set at 0.05. Results: The prevalence of caries was 81.7% and the mean decayed, missing or filled teeth score was 4.08. Prevalence was significantly higher among girls, with a prevalence ratio of 2.58 (95% CI 1.25, 5.32) (P = 0.010); among schoolchildren from mothers with lower education level, with a prevalence ratio of 3.26 (95% CI 1.32, 8.06) (P = 0.010); and among schoolchildren who had ever visited a dentist, with a prevalence ratio of 2.91 (95% CI 1.14, 7.62) (P = 0.030). Conclusions: The prevalence and severity of caries were higher than the Brazilian national average. The prevalence was statistically associated with maternal schooling, had visited a dentist, and gender. Keywords: dental caries, educational status, epidemiology, socioeconomic factors, students