Dental arch growth is influenced by several factors, including genetic and environmental factors. The tooth arch is an arch that shows the combined mesiodistal width of the teeth consisting of the maxilla and mandible. The dental arch size in each individual is different and develops through the eruption of deciduous teeth and permanent teeth. Ages 8, 9 and 10 years are periods of mixed teeth. The aim of this study was to determine differences in dental arch size between children aged 8, 9 and 10 years. This study used an observational analytic method, with cross-sectional study design. The number of samples in this study was 66 samples in each jaw, then divided into 3 age groups, namely groups of children aged 8 years, 9 years and 10 years, each group consisting of 11 boys and 11 girls. The data collection technique in this study was done by printing the maxilla and lower jaw, then measuring the dental arch width. The statistical test used is Oneway Annova on normally distributed data. The results of this study showed that there were significant differences in dental arch size between children aged 8, 9 and 10 years, namely in the width of the maxillary anterior teeth between 9 years and 10 years old children with a value of p = 0.014 (p<0.05). Based on the results of these studies, it can be concluded that there are differences in dental arch size between children aged 8, 9 and 10 years.