To know the relationship of knowledge and parental supervision about bad habits on the event of malocclusion in children. The type of research used in this study is Analytic observational with cross sectional study design. The subjects of this study were parents of children aged 8-12 years. The results of research were analyzed using Chi-Square test, it was known that there was a significant relationship between knowledge and parental supervision on children bad habits (P = 0.000). There was also a significant relationship between knowledge and parental supervision with a child's malocclusion condition caused by oral bad habits (P <0.05 (0.000 and 0.003). There is a significant relationship between knowledge and parental supervision about bad habits on the event malocclusion in children.