AIM: To compare two groups of children with externalising behaviour problems, having low and elevated caries risk, respectively. Those parameters were assessed in relation to behavioural characteristics and family structure, and to compare the caries risk assessment and gender differences in relation to children in general in the Region of Vastra Gotaland, Sweden. METHODS: Families (228) with children, aged 10-13 years, participating in parent training programmes, were recruited. Parents provided information through questionnaires regarding parental knowledge and monitoring, family warmth and conflict and family structure. Children’s behavioural characteristics, based on the Strength and Difficulties Questionnaire and the Disruptive Behaviour Disorder rating scale, were used as outcome. Data about caries risk assessment were obtained from dental records. RESULTS: Children in the elevated caries risk group showed higher mean values for conduct problems as well as impulsivity. Parents of the children in the elevated caries risk group reported more parental solicitation and less family conflicts. Children with an elevated caries risk lived more often in households with more than two children and had more often a father from a non-Nordic country. CONCLUSION: There were statistically significant more children with an elevated caries risk in the study group compared to children in general in the Region of Vastra Gotaland, both totally and within gender. Differences were observed with regard to behavioural characteristics in externalising children with an elevated risk for caries. Increased knowledge regarding behavioural characteristics in externalising children is an important parameter to be considered in caries risk assessment.