Aim The aim of this study was to examine the oral health-related behaviors in mothers and their children and the prevalence of dental caries in both. Subject and methods A sample of 2536 children and their mothers was selected from the Fifth Korean National Health and Nutrition Examination Survey. Variables were analyzed using multiple regression to evaluate the prevalence of dental caries among children and mothers, demographic socioeconomic status, and oral health-related behaviors.Results The average age of the mothers was 40.28 years and that of the children was 10.88 years. Mean DT scores were 0.67 for mothers and 0.29 for children. Mean DMFT scores were 6.63 for mothers and 1.76 for children. The higher the mother's number of decayed, missing, or filled permanent teeth (DMFT score, B = 0.076, P < 0.001) and number of decayed teeth (DT score, B = 0.032, P = 0.038) in their permanent dentition, the higher the children's DMFT score was for their permanent dentition. Children from mothers with low household income levels (B = 0.159, P = 0.043), with dental pain (B = 0.132, P = 0.032), and not using a dental mouth rinse (B = 0.135, P = 0.007) presented with higher DT scores. Children from mothers with low self-perceived oral health status (B = 0.113, P < 0.001), lower usage of dental floss (B = 0.100, P = 0.012), a lower ratio of protein intake to total energy (B = −0.017, P = 0.014), and lower ratio of fat intake (B = −0.009, P = 0.047) showed lower self-perceived oral health status. Conclusion The better the oral health status of the mother, the better the oral health status of the child was. An effective oral health and education program for mothers should be developed to promote an improved oral health status of their children.