Bad oral habit is an abnormal habit that if this habit proceeds until the children’s early education, special attention needs to be given since it has impact on craniofacial growth. Some factors causing bad oral habit among children are pathological condition, anxiety, and psychological disorder. Female children are considered to have the tendency of higher anxiety than male ones. Meanwhile, male children tend to against parents’ advice, including unwillingness to stop their bad oral habit. The aim of this research was to find out the association between gender and bad oral habit in 7-9 years old children. This research used analytical observational method with cross-sectional approach. Children among 7-9 years old were chosen as sample where oral cavity examination was given to them in order to observe clinical symptoms that might lead to bad oral habit. The children’s parents were asked to fill out questionnaire as supporting data to figure out bad oral habit in their children. The obtained data were then analyzed with chi-square test. Chi-square test result showed p-value of 0,016 (<0,05). It proved that there was association between gender and bad oral habit. Based on the result, this research conclude that there was association between gender and bad oral habit, mostly found in male children.