To determine the prevalence of dental caries in primary and permanent teeth and identify factors associated with dental caries among secondary school children in rural highland Vietnam.

This was a cross-sectional study that included 1985 secondary schoolchildren. Dental examination was performed at school using World Health Organization criteria. Data collection on demographic characteristics and knowledge, attitude, and practices related to dental caries was conducted by interviewing children. Descriptive and inferential statistics using a multivariate logistic regression model were applied.

Prevalence of caries in primary and permanent teeth was 41.1 and 68.9 %, respectively. Prevalence of caries in primary teeth in the age group 11–12 years old (59.4 %) was significantly higher than in children in the age group of 13–14 years (27.8 %; p < 0.01). Factors associated with dental caries in primary teeth were age group of 11–12 years, belonging to the Jarai ethnic group, and having inadequate knowledge or attitude related to dental caries. Factors associated with dental caries in permanent teeth were having insufficient knowledge, attitude, and practices related to dental caries.

The prevalence of dental caries in primary and permanent teeth was high among secondary school children in Vietnam’s rural highlands. It is recommended that interventions focus on younger secondary school children and the Jarai minority ethnic group, and that interventions should emphasize improving knowledge, attitudes, and practices related to dental caries.