Growth and Development of children’s teeth can be affected by several factors. The one of them is bad oral habit. If this habit is not controlled and continuous do so it will affect the growth and developments of the jaw and the teeth especially at the time of the eruption of the teeth. The purpose of this research is to identify relationship between children’s bad oral habit and delayed growth and development of permanent teeth in early mixed dentition period. The research design was the analytical study with cross-sectional approach. This research was conducted on children with age 7-9 years old in Karang Jati State Elementary School in August 2017 with 115 respondents of the total sample. The sampling technique was total sampling. The respondents were examined their oral cavity to see the clinical features of the effect of each bad oral habit (thumb sucking, nails biting, and mouth breathing) and the eruption of permanent teeth. The data were analyzed by chi-square and correlation coefficient contingency to find out the relationship between children’s bad oral habit and delayed growth and development of permanent teeth in early mixed dentition period. The result of the statistic showed that the p-value test = 0,004 (p<0,05), this result indicated that there was a relationship between children’s bad oral habit and delayed growth and development of permanent teeth in early mixed dentition period. Value of X2 = 0,262 indicated that the relationship between variables have a weak strength. The conclusion showed that there was a relationship between children’s bad oral habit and delayed growth and development of permanent teeth in early mixed dentition period.