Objective: To investigate the longitudinal association between attention deficit hyperactivity disorder (ADHD) symptoms and Internet gaming addiction among junior and senior high school students, as well as gender differences in the association, so as to provide evidence for understanding the complex interactions underlying adolescent mental health problems. Methods: Using stratified random cluster sampling, two surveys were conducted among 2 100 junior and senior high school students from six schools in Bijie City, Qianxi City, and Jinsha County, Guizhou Province, from January to March 2023 (T1) and from July to September 2023 (T2). ADHD symptoms were assessed using the Barkley Current Symptoms Scale (BCSS), and Internet gaming addiction was assessed using the Internet Gaming Disorder Scale-Short Form (IGDS9-SF). Pearson correlation analysis, cross lagged model, and multi group models were used to examine the longitudinal relationship between ADHD symptoms and Internet gaming addiction and to test gender differences. Results: The detection rate of Internet gaming addiction was 4.57% at T1. ADHD symptoms were positively correlated with Internet gaming addiction at T1 and T2 time points ( r =0.32-0.80, all P < 0.05 ). Cross lagged analysis showed that T1 ADHD symptoms positively predicted T2 ADHD symptoms ( β =0.85) and T2 Internet gaming addiction ( β =0.65) (both P <0.01). Gender stratified analyses showed that T1 ADHD symptoms positively predicted T2 ADHD symptoms among both boys and girls ( β =0.91, 0.84) and T2 Internet gaming addiction ( β =0.31, 0.29) (all P <0.01). Multi group difference tests showed a statistically significant gender difference in the T1 ADHD→T2 ADHD pathway (Wald χ 2= 7.27 , P < 0.01 ), whereas no statistically significant gender difference was found in the T1 ADHD→T2 Internet gaming addiction pathway (Wald χ 2=1.07, P > 0.05 ). Conclusions ADHD symptoms are antecedent risk factors for Internet gaming addiction among junior and senior high school students. The longitudinal predictive effect of ADHD symptoms on subsequent Internet gaming addiction is present in both boys and girls, with no gender difference in the predictive pathway.