This study aimed to investigate sex differences in the functional movement in the adolescent period. Seven hundred and thirty adolescents (365 boys) aged 16–17 years participated in the study. The participants performed standardized Functional Movement Screen™ (FMS™) protocol and a t-test was used to examine sex differences in the total functional movement screen score while the chi-square test was used to determine sex differences in the proportion of dysfunctional movement and movement asymmetries within the individual FMS tests. Girls demonstrated a higher total FMS™ score compared to boys (12.7 ± 2.3 and 12.2 ± 2.4, respectively; F=8.26, p=0.0054). Also, sex differences were present in several individual functional movement patterns where boys demonstrated a higher prevalence of dysfunctional movement compared to girls in patterns that challenge mobility and flexibility of the body, while girls underperformed in tests that have higher demands for upper-body strength and abdominal stabilization. Findings of this study suggest that sex dimorphism exists in functional movement patterns in the period of mid-adolescence. The results of this research need to be considered while using FMS™ as a screening tool as well as the reference standard for exercise intervention among the secondary school-aged population.