Objective: To describe the prevalence and association of dietary rhythm and depressive symptoms among adolescents, so as to provide a basis for improving unhealthy behavioral habits,and to promote adolescent physical and mental health. Methods: From October to December 2021, a total of 22 868 students were selected from one middle school and high school in urban and rural areas of eight cities, namely, Shenyang, Xuzhou, Shenzhen, Taiyuan, Nanchang, Zhengzhou, Chongqing, and Kunming cities, China, using a combination of purposive sampling and stratified cluster random sampling. A self administered questionnaire was used to assess adolescents dietary rhythm, and the Patient Health Questionnaire-9 (PHQ-9) was used to assess depressive symptoms. Binary Logistic regression model was employed to analyze the associations between adolescent dietary rhythm and depressive symptoms, while the associations between adolescent dietary rhythm and depressive symptoms across gender and physical activity levels were stratified by gender and physical activity levels. Results: The detection rate of depressive symptoms in adolescents was 44.4%. The respective differences in the detection rates of depressive symptoms among adolescents of different genders, physical activity levels, and dietary rhythm disorders were statistically significant ( χ 2=157.51, 105.02, 3 282.50, P <0.01). Taking the low disordered dietary rhythm group as the reference, binary Logistic regression analyses showed that after adjusting for confounding factors such as age, gender，family location, family economic situation, whether only child, parental education level, and learning burden, physical activity levels, depressive symptoms were positively correlated with adolescents in the moderate disordered dietary rhythm group ( OR=2.63, 95%CI =2.45-2.83) and the high disordered dietary rhythm group ( OR=6.38, 95%CI = 5.93- 6.86). In addition, after stratifying by gender, dietary rhythm were positively correlated with depressive symptoms. The moderate disordered group (male: OR=2.62, 95%CI =2.37-2.89, female: OR=2.67, 95%CI =2.40-2.97) and the highly disordered group (male: OR=5.74, 95%CI =5.19-6.35, female: OR=7.11, 95%CI =6.40-7.89) were positively correlated with depressive symptoms. After stratification by physical activity levels, low, moderate and above physical activity levels among adolescents in the disordered dietary rhythm group (low physical activity: OR=2.91, 95%CI =2.58-3.29, moderate and above physical activity: OR= 2.50, 95%CI =2.28-2.74), high disordered group (low physical activity: OR=6.51, 95%CI =5.94- 7.13 , moderate and higher physical activity: OR=6.18, 95%CI =5.47-6.97) were positively associated with depressive symptoms ( P <0.01). There was an interaction between dietary rhythm and physical activity levels in regard to the development of depressive symptoms in adolescents, taking the group with moderate and above physical activity levels and low disordered dietary rhythm as the reference,the detection rate of which was higher in adolescents with low levels of physical activity and those in the moderate or high disordered dietary rhythm group ( OR=1.50, 3.90, 95%CI=1.39-1.61, 3.63-4.19, P <0.01). Conclusions Dietary rhythm disorders were found to be positively associated with depressive symptoms in adolescents. Regular dietary behaviors and increased physical activity play an important positive role in promoting adolescent mental health.