Children depend on their parents and caretakers for maintenance of their oral health. Parents play a major role in both preventive and treatment regime in these children. This study was conducted with the aim of evaluating the influence of parental education on knowledge, attitude, and practice of mothers regarding oral health of primary schoolchildren in Chennai. A 15-item self-administered questionnaire was used among 465 parents of preschool children in Chennai, of which 432 mothers returned the filled questionnaire. The data collected were subjected to statistical analysis using frequency of responses and chi-square test (p < 0.01). Data were analyzed using statistical package. Of the 432 mothers who participated in the study, 150 (35%) have studied up to school level and 282 (65%) have completed diploma/degree. The knowledge of mothers regarding the knowledge of importance of oral health for general health is appreciable, but the awareness of proper brushing habit, treatment of caries, and importance of dental visits is less in mothers who have school education when compared with graduate mothers. Mothers who are graduates are more aware of the importance of oral health in children, treatment of dental caries, and brushing technique than mothers with school education. Hence, it is essential that government and health care providers impart oral health knowledge to mothers, as they are the role-models for their children. Gurunathan D, Moses J, Arunachalam SK. Knowledge, Attitude, and Practice of Mothers regarding Oral Hygiene of Primary School children in Chennai, Tamil Nadu, India. Int J Clin Pediatr Dent 2018;11(4):338-343.