To study the sexual maturity at puberty and interrelation between pubertal growth peak and sexual maturity, 68 malocclusions (female 44, male 24) were longitudinally studied for 4 years and cross-sectional samples of 210 malocclusions were studied together. The pubertal growth peak was determined by stature increment and sexual maturity was studied using developmental stages of pubic hair and breast, menarche in female and those of pubic hair in male. The following results were obtained. 1. Mean age at menarche was 12.8 years and it was 11.8 months later than PHV. 2. At pubertal growth peak, developmental stage 2 (54.2%) and 3 (29.2%) of pubic hair were most in male, and stage 1 (72.7%) and 2 (20.5%) were most in female. 3. At pubertal growth peak, the developmental stage 2 (50%) of breast was most and the stage 3 (43.2%) was next. 4. In interrelation between skeletal growth and sexual maturity, PHV had most high correlation with menarche and stage 3 of breast, and menarche had most high correlation with stage 3 of breast. 5. Appearance of remarkable sexual maturity suggested that the PHV was passed already.