Aim: The objective of this study was to investigate the association between the caries experience and oral-health-related behavior of Kuwaiti preschool children and their mothers. Materials and methods: A convenience sample of 84 participants (42 child–mother pairs) was selected. Data regarding children's and mothers’ demographics, oral hygiene practices, and dietary habits were obtained by questionnaires. Oral clinical examinations were carried out on the participant children and mothers to determine their caries experience (decayed, missing, and filled teeth index-dmft/DMFT). Results: An estimated 19% of children were caries-free and 66% of mothers have untreated caries. The mean dmft index of the preschool children was 3.90 ± 2.9, and the mean DMFT index of their mothers was 12.38 ± 5.4. Mothers’ untreated caries was significantly associated with their children's untreated caries (r = 0.183, p < 0.05). No correlation was found between the brushing frequencies of children and their mothers (p = 0.582). High consumption of sugary snacks and sugary beverages was detected among the children and mothers with a significant association (p < 0.05). The mean dmft of the children was found to be significantly lower among the young mothers, less than 30 years, (2.4 ± 2.1) compared to that among the mothers older than 30 years (4.3 ± 2.9, p < 0.05). Conclusion: There was a high prevalence of early childhood caries in the preschool children studied. A positive correlation was found between the dental caries experience and sugar consumption of the Kuwaiti preschool children and those of their mothers. Clinical significance: The oral health status and dietary habits of mothers are potentially significant risk factors for the development of early childhood caries in their children. Pediatric dentists need to identify the main caries risk factors in their community in order to implement appropriate preventive dental care and educational programs.