Objective: To investigate the relationship between pubertal timing and depressive symptoms among high school students in Suzhou, so as to provide scientific evidence for promoting adolescents mental health. Methods: From October 2023 to January 2024, 3 369 students were selected from 20 high schools in Suzhou using stratified cluster random sampling method. Physical examinations and questionnaire surveys were conducted. The Preece & Baines growth Model 1 was used to calculate the age at take off of height velocity (ATO) and age at peak height velocity (APHV), categorizing students into three groups: early pubertal timing group (< P 15 ), ontime group ( P 15 - P 85 ), and delayed group (> P 85 ). Binary Logistic regression was used to analyze its association with depressive symptoms. Results: The ATO for male and female high school students in Suzhou was (9.35±1.23) and ( 8.12 ±1.52) years old, respectively. The mean APHV was (12.35±0.74) years old for boys and (10.91±0.82) years old for girls. The overall prevalence of depressive symptoms was 34.22%, with no statistically significant gender difference ( χ 2=0.42, P =0.52). Significant differences in depressive symptom prevalence were observed across grade levels, breakfast frequency, weekly days of moderate to vigorous physical activity, daily sleep duration, history of school bullying, and the presence of Internet addiction ( χ 2=5.03-69.21, all P < 0.05 ). After adjusting for age, body mass index, region, boarding status, breakfast frequency, weekly moderate to vigorous physical activity days, sleep duration, campus bullying, and presence of Internet addiction, Logistic regression analysis revealed that when ATO was used to evaluate pubertal timing, the risk of depressive symptoms in the delayed group of boys was 1.65 times that of the on time group (95% CI =1.24-2.19); when APHV was used to evaluate pubertal timing, the risks of depressive symptoms in the early pubertal timing group and delayed group of boys were 1.43 times (95% CI =1.07-1.91) and 1.41 times (95% CI =1.05-1.88) of that of the on time group, respectively (all P <0.05). No statistically significant associations were found among females (all P > 0.05 ). Conclusion The prevalence of depressive symptoms among high school students in Suzhou is relatively high, and both early and delayed puberty timing in boys are associated with depressive symptoms.