OBJECTIVE: This research measures the regional GMV (rGMV) of the cerebellum, attention, Executive Function (EF) and we aimed to identify their correlation and sex differences in children and adolescents. METHODS: Subjects comprised 114 children (male = 62, female = 52, 12.44 +/- 2.99 years old) from South Korea. Participants were divided into three groups by age (age 6-9, 10-13, and 14-17). The Stroop Color and Word Test (SCWT), Wisconsin Card Sorting Test (WCST), and Advanced Test of Attention (ATA) were used to estimate executive function. Magnetic resonance imaging (MRI) images were analyzed with Regional Voxel-Based Morphometry Analysis. RESULTS: The correlations between cerebellar rGMV and SCWT, WCST, and ATA subcategories showed difference by age and sex. In 6-9 age group, girls showed more overall correlations with cerebellar regions than boys, in WCST Categories Completed and ATA results. In age 10-13 group, more regions of cerebellum corresponded to SCWT subcategories in girls. Nevertheless, more correlation between cerebellar rGMV, WCST subcategories and some ATA subtests were observed in boys in the same age group. In the adolescent group, aged 14-17, boys showed more correlation with cerebellar rGMV, while girls showed little correlation. CONCLUSION: This study highlights that sex-different cerebellum maturation in adolescence might be correlated with EF and attention. These results provides evidence that cerebellum modulates higher cognitive functioning during child development.