The aim of this study was to assess the prevalence, extent, severity, intraoral distribution and risk indicators for erosive tooth wear (ETW) among 12-year-old schoolchildren from Montevideo, Uruguay. A population-based, cross-sectional survey was conducted using a representative sample of 1,136 12-year-old schoolchildren attending public and private schools. Parents answered questions on socioeconomic status and general health. Schoolchildren answered questions on dietary and oral hygiene habits. Two calibrated examiners recorded ETW on permanent teeth according to the Basic Erosive Wear Examination (BEWE) score system. Logistic regression models were performed to assess the association between the predictor variables and the prevalence of ETW (overall and severe ETW). Odds ratios (OR) and the respective 95% confidence intervals (CI) were estimated. The prevalence of ETW was 52.9%, being mild erosion (BEWE = 1) in the vast majority of cases (48.5%). Severe erosion (BEWE ≥2) was detected in 4.4% of schoolchildren. The overall prevalence of ETW differed significantly between categories of gender and socioeconomic status, but only between gender in the severe ETW analysis. The overall extent of ETW was significantly different between categories of gender, socioeconomic status, and swish before swallow. The extent of severe ETW differed between categories of swish before swallow and brushing frequency. In the logistic regression analysis, no association was found between the studied variables and the overall prevalence of ETW. Males were more likely to have severe ETW than females (OR = 3.22, 95% CI = 1.50-6.89). ETW may be considered a public health problem among 12-year-old-Uruguayan schoolchildren.