The aim of this study was to compare the proprioceptive accuracy in the dominant and nondominant lower extremities between early and late stages of adolescence in boys. Participants displaying sexual development consistent with Tanner stages I or II were included in the early adolescent group, and those displaying development consistent with Tanner Stages IV or V were included in the late adolescent group. Proprioception was evaluated using the following 4 tests: one-leg-standing test, a single-limb-hopping test, an active angle-reproduction test, and a passive angle-reproduction test. There were statistically significant differences between the early and late stages of adolescence in nondominant ankles with regard to this single-limbstanding test. There were no statistically significant differences between the early and late adolescent stages, and between dominant and nondominant extremities with regard to the single-limb-hopping test. There were no statistically significant differences between early and late adolescent stages with regard to passive and active ankle plantar-and dorsiflexion position reproduction. Based on these findings, we concluded that sexual maturation categorized by Tanner stage does not affect proprioceptive ability in adolescent individuals. Clinical relevance: This method, as a clinical assessment of detecting deficits in neuromuscular control examined by foot and ankle surgeons and a rehabilitation technique to treat functional instability of the ankle used by physical therapists, might be applied to adolescents. Therefore, clinicians may obtain reliable information from the functional test battery during the assessment of ankle joint performance in adolescents. (C) 2011 by the American College of Foot and Ankle Surgeons. All rights reserved.