To analyze the gender disparities in the association of low/reduced BMDwith height in Chinese adolescents at the stage of growth spurt. A total of 8152 adolescents aged 12-14years old were included based on a cross-sectional study in Tianjin, China. Height and weight were measured with standard equipment. BMD was measured using the method of quantitative ultrasound. Adolescents with Z ≤ - 2.0 or - 2.0 < Z ≤ - 1.0 were defined as "low BMD" or "reduced BMD". The total low/reduced BMD rate was 22.0% in Chinese adolescents aged 12-14years old, and boys were more likely to have low/reduced BMD than girls (30.1% vs. 12.9%, P < 0.001). The rate of low/reduced BMD significantly increased with age in boys (Ptrend = 0.019), whereas decreased with age in girls (Ptrend = 0.018). We found significant interaction effect between gender and height standard deviation score (height-Z)in the association with low/reduced BMD (Pinteraction < 0.001). There was a positive association of height-Z among boys (OR = 1.30, 95%CI 1.21-1.39, P < 0.001), meanwhile low/reduced BMD was inversely associated with height-Z among girls (OR = 0.85, 95%CI 0.78-0.94, P < 0.001). Our study suggested strong gender disparities in the impact of height on BMD in Chinese adolescentsaged 12-14 years old, where the association between low/reduced BMD and height was positive among boys but inverse among girls. The study provides evidence on the early prevention and the risk factor identification of low/reduced BMD and childhood fractures.