The objective of this study was to assess the association of untreated traumatic dental injuries (TDI) with individual-, sociodemographic- and school-related factors among 12-year-old schoolchildren in Midwest Brazil. This cross-sectional study was carried out in 2010 in the city of Goiania, Brazil. A random sample of 2075 schoolchildren was examined and interviewed. Untreated TDI in the permanent incisors was assessed using the methodology of the Brazilian National Oral Health Survey. Rao-Scott test and multinomial logistic regression were used to analyze the associations between independent variables and three categories of TDI, using a hierarchical method. Independent variables were children’s sex, self rated color/race and size of incisal overjet, their mother’s level of schooling, and the schools’ type and geographic location. The prevalence of trauma was 17.3% (CI 95% = 15.2–19.4); enamel fractures were the most common TDI (13.1%). In the adjusted model, a higher chance of having two or more teeth with TDI was found among boys, those whose mothers had lowest level of schooling, and those attending schools located in health districts with lower socioeconomic indicators. It was concluded that the prevalence of TDI was low and that it was associated with individual factors as well as the school environments. Full article